How do we know the LHC results are robust?
$begingroup$
Nature article on reproducibility in science.
According to that article, a (surprisingly) large number of experiments aren't reproducible, or at least there have been failed attempted reproductions. In one of the figures, it's said that 70% of scientists in physics & engineering have failed to reproduce someone else's results, and 50% have failed to reproduce their own.
Clearly, if something cannot be reproduced, its veracity is called into question. Also clearly, because there's only one particle accelerator with the power of the LHC in the world, we aren't able to independently reproduce LHC results. In fact, because 50% of physics & engineering experiments aren't reproducible by the original scientists, one might expect there's a 50% chance that if the people who originally built the LHC built another LHC, they will not reach the same results. How, then, do we know that the LHC results (such as the discovery of the Higgs boson) are robust? Or do we not know the LHC results are robust, and are effectively proceeding on faith that they are?
EDIT: As pointed out by Chris Hayes in the comments, I misinterpreted the Nature article. It says that 50% of physical scientists have failed to reproduce their own results, which is not the same statement as 50% of physics experiments aren't reproducible. This significantly eases the concern I had when I wrote the question. I'm leaving the question here however, because the core idea - how can we know the LHC's results are robust when we only have one LHC? - remains the same, and because innisfree wrote an excellent answer.
particle-physics large-hadron-collider data-analysis
$endgroup$
|
show 7 more comments
$begingroup$
Nature article on reproducibility in science.
According to that article, a (surprisingly) large number of experiments aren't reproducible, or at least there have been failed attempted reproductions. In one of the figures, it's said that 70% of scientists in physics & engineering have failed to reproduce someone else's results, and 50% have failed to reproduce their own.
Clearly, if something cannot be reproduced, its veracity is called into question. Also clearly, because there's only one particle accelerator with the power of the LHC in the world, we aren't able to independently reproduce LHC results. In fact, because 50% of physics & engineering experiments aren't reproducible by the original scientists, one might expect there's a 50% chance that if the people who originally built the LHC built another LHC, they will not reach the same results. How, then, do we know that the LHC results (such as the discovery of the Higgs boson) are robust? Or do we not know the LHC results are robust, and are effectively proceeding on faith that they are?
EDIT: As pointed out by Chris Hayes in the comments, I misinterpreted the Nature article. It says that 50% of physical scientists have failed to reproduce their own results, which is not the same statement as 50% of physics experiments aren't reproducible. This significantly eases the concern I had when I wrote the question. I'm leaving the question here however, because the core idea - how can we know the LHC's results are robust when we only have one LHC? - remains the same, and because innisfree wrote an excellent answer.
particle-physics large-hadron-collider data-analysis
$endgroup$
4
$begingroup$
I think it is worth pointing out that the LHC doesn't just do one particle collision and then say the experiment is completed. How much do you know about what goes into such experiments, how many times they are actually repeated, and then how the data is analyzed from there?
$endgroup$
– Aaron Stevens
7 hours ago
3
$begingroup$
I was asking if you had looked into the efforts taken to make sure the results from the LHC are good results and not just mistakes. Also the LHC isn't the only particle collider in existence.
$endgroup$
– Aaron Stevens
7 hours ago
5
$begingroup$
For more about this important question than you may have bargained for, look for discussions about the "look-elsewhere effect" in the statistical analysis of the data from the mostly-independent ATLAS and CMS experiments at the LHC, especially in the context of their joint discovery of the Higgs particle.
$endgroup$
– rob♦
6 hours ago
5
$begingroup$
@Allure "Half [of scientists] have failed to reproduce their own experiments" is an enormously different statement from "half of all experiments are non-reproducible". The former statement (from the Nature article) includes scientists who have failed to reproduce a single one of their experiments, even if they successfully reproduced 99 out of 100. See page 10 of the questionnaire for the exact wording.
$endgroup$
– Chris Hayes
3 hours ago
1
$begingroup$
@ChrisHayes My thought exactly! Furthermore, a failed attempt to replicate an experiment doesn't necessarily mean that the original experiment is "non-reproducible".
$endgroup$
– jkej
2 hours ago
|
show 7 more comments
$begingroup$
Nature article on reproducibility in science.
According to that article, a (surprisingly) large number of experiments aren't reproducible, or at least there have been failed attempted reproductions. In one of the figures, it's said that 70% of scientists in physics & engineering have failed to reproduce someone else's results, and 50% have failed to reproduce their own.
Clearly, if something cannot be reproduced, its veracity is called into question. Also clearly, because there's only one particle accelerator with the power of the LHC in the world, we aren't able to independently reproduce LHC results. In fact, because 50% of physics & engineering experiments aren't reproducible by the original scientists, one might expect there's a 50% chance that if the people who originally built the LHC built another LHC, they will not reach the same results. How, then, do we know that the LHC results (such as the discovery of the Higgs boson) are robust? Or do we not know the LHC results are robust, and are effectively proceeding on faith that they are?
EDIT: As pointed out by Chris Hayes in the comments, I misinterpreted the Nature article. It says that 50% of physical scientists have failed to reproduce their own results, which is not the same statement as 50% of physics experiments aren't reproducible. This significantly eases the concern I had when I wrote the question. I'm leaving the question here however, because the core idea - how can we know the LHC's results are robust when we only have one LHC? - remains the same, and because innisfree wrote an excellent answer.
particle-physics large-hadron-collider data-analysis
$endgroup$
Nature article on reproducibility in science.
According to that article, a (surprisingly) large number of experiments aren't reproducible, or at least there have been failed attempted reproductions. In one of the figures, it's said that 70% of scientists in physics & engineering have failed to reproduce someone else's results, and 50% have failed to reproduce their own.
Clearly, if something cannot be reproduced, its veracity is called into question. Also clearly, because there's only one particle accelerator with the power of the LHC in the world, we aren't able to independently reproduce LHC results. In fact, because 50% of physics & engineering experiments aren't reproducible by the original scientists, one might expect there's a 50% chance that if the people who originally built the LHC built another LHC, they will not reach the same results. How, then, do we know that the LHC results (such as the discovery of the Higgs boson) are robust? Or do we not know the LHC results are robust, and are effectively proceeding on faith that they are?
EDIT: As pointed out by Chris Hayes in the comments, I misinterpreted the Nature article. It says that 50% of physical scientists have failed to reproduce their own results, which is not the same statement as 50% of physics experiments aren't reproducible. This significantly eases the concern I had when I wrote the question. I'm leaving the question here however, because the core idea - how can we know the LHC's results are robust when we only have one LHC? - remains the same, and because innisfree wrote an excellent answer.
particle-physics large-hadron-collider data-analysis
particle-physics large-hadron-collider data-analysis
edited 2 hours ago
Allure
asked 8 hours ago
AllureAllure
2,072724
2,072724
4
$begingroup$
I think it is worth pointing out that the LHC doesn't just do one particle collision and then say the experiment is completed. How much do you know about what goes into such experiments, how many times they are actually repeated, and then how the data is analyzed from there?
$endgroup$
– Aaron Stevens
7 hours ago
3
$begingroup$
I was asking if you had looked into the efforts taken to make sure the results from the LHC are good results and not just mistakes. Also the LHC isn't the only particle collider in existence.
$endgroup$
– Aaron Stevens
7 hours ago
5
$begingroup$
For more about this important question than you may have bargained for, look for discussions about the "look-elsewhere effect" in the statistical analysis of the data from the mostly-independent ATLAS and CMS experiments at the LHC, especially in the context of their joint discovery of the Higgs particle.
$endgroup$
– rob♦
6 hours ago
5
$begingroup$
@Allure "Half [of scientists] have failed to reproduce their own experiments" is an enormously different statement from "half of all experiments are non-reproducible". The former statement (from the Nature article) includes scientists who have failed to reproduce a single one of their experiments, even if they successfully reproduced 99 out of 100. See page 10 of the questionnaire for the exact wording.
$endgroup$
– Chris Hayes
3 hours ago
1
$begingroup$
@ChrisHayes My thought exactly! Furthermore, a failed attempt to replicate an experiment doesn't necessarily mean that the original experiment is "non-reproducible".
$endgroup$
– jkej
2 hours ago
|
show 7 more comments
4
$begingroup$
I think it is worth pointing out that the LHC doesn't just do one particle collision and then say the experiment is completed. How much do you know about what goes into such experiments, how many times they are actually repeated, and then how the data is analyzed from there?
$endgroup$
– Aaron Stevens
7 hours ago
3
$begingroup$
I was asking if you had looked into the efforts taken to make sure the results from the LHC are good results and not just mistakes. Also the LHC isn't the only particle collider in existence.
$endgroup$
– Aaron Stevens
7 hours ago
5
$begingroup$
For more about this important question than you may have bargained for, look for discussions about the "look-elsewhere effect" in the statistical analysis of the data from the mostly-independent ATLAS and CMS experiments at the LHC, especially in the context of their joint discovery of the Higgs particle.
$endgroup$
– rob♦
6 hours ago
5
$begingroup$
@Allure "Half [of scientists] have failed to reproduce their own experiments" is an enormously different statement from "half of all experiments are non-reproducible". The former statement (from the Nature article) includes scientists who have failed to reproduce a single one of their experiments, even if they successfully reproduced 99 out of 100. See page 10 of the questionnaire for the exact wording.
$endgroup$
– Chris Hayes
3 hours ago
1
$begingroup$
@ChrisHayes My thought exactly! Furthermore, a failed attempt to replicate an experiment doesn't necessarily mean that the original experiment is "non-reproducible".
$endgroup$
– jkej
2 hours ago
4
4
$begingroup$
I think it is worth pointing out that the LHC doesn't just do one particle collision and then say the experiment is completed. How much do you know about what goes into such experiments, how many times they are actually repeated, and then how the data is analyzed from there?
$endgroup$
– Aaron Stevens
7 hours ago
$begingroup$
I think it is worth pointing out that the LHC doesn't just do one particle collision and then say the experiment is completed. How much do you know about what goes into such experiments, how many times they are actually repeated, and then how the data is analyzed from there?
$endgroup$
– Aaron Stevens
7 hours ago
3
3
$begingroup$
I was asking if you had looked into the efforts taken to make sure the results from the LHC are good results and not just mistakes. Also the LHC isn't the only particle collider in existence.
$endgroup$
– Aaron Stevens
7 hours ago
$begingroup$
I was asking if you had looked into the efforts taken to make sure the results from the LHC are good results and not just mistakes. Also the LHC isn't the only particle collider in existence.
$endgroup$
– Aaron Stevens
7 hours ago
5
5
$begingroup$
For more about this important question than you may have bargained for, look for discussions about the "look-elsewhere effect" in the statistical analysis of the data from the mostly-independent ATLAS and CMS experiments at the LHC, especially in the context of their joint discovery of the Higgs particle.
$endgroup$
– rob♦
6 hours ago
$begingroup$
For more about this important question than you may have bargained for, look for discussions about the "look-elsewhere effect" in the statistical analysis of the data from the mostly-independent ATLAS and CMS experiments at the LHC, especially in the context of their joint discovery of the Higgs particle.
$endgroup$
– rob♦
6 hours ago
5
5
$begingroup$
@Allure "Half [of scientists] have failed to reproduce their own experiments" is an enormously different statement from "half of all experiments are non-reproducible". The former statement (from the Nature article) includes scientists who have failed to reproduce a single one of their experiments, even if they successfully reproduced 99 out of 100. See page 10 of the questionnaire for the exact wording.
$endgroup$
– Chris Hayes
3 hours ago
$begingroup$
@Allure "Half [of scientists] have failed to reproduce their own experiments" is an enormously different statement from "half of all experiments are non-reproducible". The former statement (from the Nature article) includes scientists who have failed to reproduce a single one of their experiments, even if they successfully reproduced 99 out of 100. See page 10 of the questionnaire for the exact wording.
$endgroup$
– Chris Hayes
3 hours ago
1
1
$begingroup$
@ChrisHayes My thought exactly! Furthermore, a failed attempt to replicate an experiment doesn't necessarily mean that the original experiment is "non-reproducible".
$endgroup$
– jkej
2 hours ago
$begingroup$
@ChrisHayes My thought exactly! Furthermore, a failed attempt to replicate an experiment doesn't necessarily mean that the original experiment is "non-reproducible".
$endgroup$
– jkej
2 hours ago
|
show 7 more comments
3 Answers
3
active
oldest
votes
$begingroup$
That's a really great question. The 'replication crisis' is that many effects in social sciences couldn't be reproduced. There are many factors leading to this phenomenon, including
- Weak standards of evidence, e.g., $2sigma$ evidence required to demonstrate an effect
- Researchers (subconsciously or otherwise) conducting bad scientific practice by selectively reporting and publishing significant results. E.g. considering many different effects until they find a significant effect or collecting data until they find a significant effect.
- Poor training in statistical methods.
I'm not entirely sure about the exact efforts that the LHC experiments are making to ensure that they don't suffer the same problems. But let me say some things that should at least put your mind at ease:
- Particle physics typically requires a high-standard of evidence for discoveries ($5sigma$)
- The results at the LHC are already replicated!
- There are several detectors placed around the LHC ring. Two them, called ATLAS and CMS, are general purpose detectors for Standard Model and Beyond the Standard Model physics. Both of them found compelling evidence for the Higgs boson. They are in principle completely independent (though in practice staff switch experiments, experimentalists from each experiment presumably talk and socialize with each other etc, so possibly a very small dependence in analysis choices etc).
- The Tevatron, a similar collider experiment in the USA operating at lower-energies, found direct evidence for the Higgs boson.
- The Higgs boson was observed several datasets collected at the LHC
- The LHC (typically) publishes findings regardless of their statistical significance, i.e., significant results are not selectively reported.
- The LHC teams are guided by statistical committees, hopefully ensuring good practice
- The LHC is in principle committed to open data, which means a lot of the data should at some point become public. This is one recommendation for helping the crisis in social sciences.
- Typical training for experimentalists at the LHC includes basic statistics (although in my experience LHC experimentalits are still subject to the same traps and misinterpretations as everyone else).
- All members (thousands) of the experimental teams are authors on the papers. The incentive for bad practices such as $p$-hacking is presumably slightly lowered, as you cannot 'discover' a new effect and publish it only under your own name, and have improved job/grant prospects. This incentive might be a factor in the replication crisis in social sciences.
- All papers are subject to internal review (which I understand to be quite rigorous) as well as external review by a journal
- LHC analyses are often (I'm not sure who plans or decides this) blinded. This means that the experimentalists cannot tweak the analyses depending on the result. They are 'blind' to the result, make their choices, then unblind it only at the end. This should help prevent $p$-hacking
- LHC analysis typically (though not always) report a global $p$-value, which has beeen corrected for multiple comparisons (the look-elsewhere effect).
If anything, there is a suspicion that the practices at the LHC might even result in the opposite of the 'replication crisis;' analyses that find effects that are somewhat significant might be examined and tweaked until they decrease.
$endgroup$
2
$begingroup$
This is an excellent answer! I think it should be further emphasized how different $2sigma$ is from $5 sigma$. Using the standard $2 sigma$ conventions of social science, you have a 5% chance of getting a significant result every time you test a completely false hypothesis. (And this can easily be boosted by a factor of 10 by $p$-hacking techniques, plus you can report something like $p = 0.1$ as "trending towards significance".) Asking for $5 sigma$ is not merely being $5/2$ as rigorous, the corresponding $p$-value cutoff is roughly $0.0000003$.
$endgroup$
– knzhou
2 hours ago
add a comment |
$begingroup$
In addition to innisfree's excellent list, there's another fundamental difference between modern physics experiments and human-based experiments: While the latter tend to be exploratory, physics experiments these days are primarily confirmatory.
In particular, we have theories (sometimes competing theories) that model our idea of how physics works. These theories make specific predictions about the kinds of results we ought to see, and physics experiments are generally then built to discriminate between the various predictions, which are typically either of the form "this effect happens or doesn't" (jet quenching, dispersion in the speed of light due to quantized space), or "this variable has some value" (the mass of the Higgs boson). We use computer simulations to produce pictures of what the results would look like in the different cases and then match the experimental data with those models; nearly always, what we get matches one or the other of the suspected cases. In this way, experimental results in physics are rarely shocking.
Occasionally, however, what we see is something really unexpected, such as the time OPERA seemed to have observed faster-than-light motion—or, for that matter, Rutherford's gold-foil experiment. In these cases, priority tends to go toward reproducing the effect if possible and explaining what's going on (which usually tends to be an error of some sort, such as the miswired cable in OPERA, but does sometimes reveal something totally new, which then tends to become the subject of intense research itself until the new effect is understood well enough to start making models of it again).
New contributor
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$begingroup$
I understand what you mean, but "match experimental data with models" sounds like there is ample reason to expect confirmation bias if not done properly.
$endgroup$
– Scrontch
4 hours ago
add a comment |
$begingroup$
The paper seems to be a statistical analysis of opinions, and in no way is rigorous enough to raise a question about the LHC. It is statistics about undisclosed statistics.
Here is a simpler example for statistics of failures: Take an Olympics athlete. How many failures before breaking the record? Is the record not broken because there may have been a thousand failures before breaking it?
What about the hundreds of athletes who try to reproduce and get a better record? Should they not try?
The statistics of failed experiments is similar: There is a goal (actually thousands of goals depending on the physics discipline), and a number of trials to reach the goal, though the olympics record analogy should not be taken too far, only to point out the difficulty of combining statistics from a large number of sets. In physics there may be wrong assumptions, blind alleys, logical errors... that may contribute to the failure of reproducibility. The confidence level from statistical and systematic errors are used to define the robustness of a measurement.
from the question:
"because 50% of physics & engineering experiments aren't reproducible by the original scientists",
This is a fake statement from a dubious poll. The statistical significance of the "not reproducible " has not been checked in the poll. Only if it were a one standard deviation result , there exists almost a 50% a probability of the next trial not to reproduce.
one might expect there's a 50% chance that if the people who originally built the LHC built another LHC, they will not reach the same results
No way, because engineering and physics analysis at the LHC are over the 4 sigma level, and the probability of negation is small. Even a 3sigma level has confidence 99% , so the chance is in no way 50%.
We know the LHC results are robust because there are two major and many smaller experiments trying for the same goals. The reason there are two experiments is so that systematic errors in one will not give spurious results. We trust that the measurement statistics that give the end results are correct, as we trust for the record breaking run that the measured times and distances are correct.
(And LHC is not an experiment. It is where experiments can be carried out depending on the efforts and ingenuity of researchers, it is the field where the Olympics takes place.)
The robustness of scientific results depends on the specific experimental measurements, not on integrating over all disparate experiments ever made. Bad use of statistics. For statistics of statistics, i.e. the confidence level of the "failed experiments" have to be done rigorously and the paper is not doing that.
Another way to look at it: If there were no failures , would the experiments mean anything? They would be predictable by pen and paper.
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8
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I'm not sure I buy the Olympics analogy. Failed attempts at breaking a record isn't the same thing as a failed attempt to reproduce an experiment. It also sounds like you are saying we should just cherry pick what does work and ignore when it fails.
$endgroup$
– Aaron Stevens
7 hours ago
6
$begingroup$
You're just making it sound like if just try hard enough we can reproduce anything (break the record) , but this is not always the case. Not being able to reproduce experiment A could mean that something was wrong with experiment A and that we shouldn't try to make too many predictions (or any at all) based on experiment A. We wouldn't want to keep chasing it (trying to break the record)
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– Aaron Stevens
6 hours ago
3
$begingroup$
The whole concern about the replication crisis isn't that effects exist but we aren't skilled enough to reproduce them! It's that the effects didn't reproduce because they don't exist, and lots of papers are being published about effects that don't exist
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– innisfree
6 hours ago
2
$begingroup$
So if we must use the Olympics analogy, it's more like lots and lots of excitement about records being smashed, and it later turning out they were all heavily wind-assisted or aided by doping etc, i.e. spurious not genuine.
$endgroup$
– innisfree
6 hours ago
1
$begingroup$
I feel like this answer misses the heart of the question, which is: given that the reproducibility in physics & engineering is only 50% (and that's only if we get the people who built the LHC to do it again), how can we be sure that if we build another LHC, we will still find the Higgs boson? There are two experiments, but if I'm not mistaken, both of them use the same accelerator, so it's still conceivable that if we build another accelerator we will not see the Higgs anymore.
$endgroup$
– Allure
4 hours ago
|
show 11 more comments
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3 Answers
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3 Answers
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$begingroup$
That's a really great question. The 'replication crisis' is that many effects in social sciences couldn't be reproduced. There are many factors leading to this phenomenon, including
- Weak standards of evidence, e.g., $2sigma$ evidence required to demonstrate an effect
- Researchers (subconsciously or otherwise) conducting bad scientific practice by selectively reporting and publishing significant results. E.g. considering many different effects until they find a significant effect or collecting data until they find a significant effect.
- Poor training in statistical methods.
I'm not entirely sure about the exact efforts that the LHC experiments are making to ensure that they don't suffer the same problems. But let me say some things that should at least put your mind at ease:
- Particle physics typically requires a high-standard of evidence for discoveries ($5sigma$)
- The results at the LHC are already replicated!
- There are several detectors placed around the LHC ring. Two them, called ATLAS and CMS, are general purpose detectors for Standard Model and Beyond the Standard Model physics. Both of them found compelling evidence for the Higgs boson. They are in principle completely independent (though in practice staff switch experiments, experimentalists from each experiment presumably talk and socialize with each other etc, so possibly a very small dependence in analysis choices etc).
- The Tevatron, a similar collider experiment in the USA operating at lower-energies, found direct evidence for the Higgs boson.
- The Higgs boson was observed several datasets collected at the LHC
- The LHC (typically) publishes findings regardless of their statistical significance, i.e., significant results are not selectively reported.
- The LHC teams are guided by statistical committees, hopefully ensuring good practice
- The LHC is in principle committed to open data, which means a lot of the data should at some point become public. This is one recommendation for helping the crisis in social sciences.
- Typical training for experimentalists at the LHC includes basic statistics (although in my experience LHC experimentalits are still subject to the same traps and misinterpretations as everyone else).
- All members (thousands) of the experimental teams are authors on the papers. The incentive for bad practices such as $p$-hacking is presumably slightly lowered, as you cannot 'discover' a new effect and publish it only under your own name, and have improved job/grant prospects. This incentive might be a factor in the replication crisis in social sciences.
- All papers are subject to internal review (which I understand to be quite rigorous) as well as external review by a journal
- LHC analyses are often (I'm not sure who plans or decides this) blinded. This means that the experimentalists cannot tweak the analyses depending on the result. They are 'blind' to the result, make their choices, then unblind it only at the end. This should help prevent $p$-hacking
- LHC analysis typically (though not always) report a global $p$-value, which has beeen corrected for multiple comparisons (the look-elsewhere effect).
If anything, there is a suspicion that the practices at the LHC might even result in the opposite of the 'replication crisis;' analyses that find effects that are somewhat significant might be examined and tweaked until they decrease.
$endgroup$
2
$begingroup$
This is an excellent answer! I think it should be further emphasized how different $2sigma$ is from $5 sigma$. Using the standard $2 sigma$ conventions of social science, you have a 5% chance of getting a significant result every time you test a completely false hypothesis. (And this can easily be boosted by a factor of 10 by $p$-hacking techniques, plus you can report something like $p = 0.1$ as "trending towards significance".) Asking for $5 sigma$ is not merely being $5/2$ as rigorous, the corresponding $p$-value cutoff is roughly $0.0000003$.
$endgroup$
– knzhou
2 hours ago
add a comment |
$begingroup$
That's a really great question. The 'replication crisis' is that many effects in social sciences couldn't be reproduced. There are many factors leading to this phenomenon, including
- Weak standards of evidence, e.g., $2sigma$ evidence required to demonstrate an effect
- Researchers (subconsciously or otherwise) conducting bad scientific practice by selectively reporting and publishing significant results. E.g. considering many different effects until they find a significant effect or collecting data until they find a significant effect.
- Poor training in statistical methods.
I'm not entirely sure about the exact efforts that the LHC experiments are making to ensure that they don't suffer the same problems. But let me say some things that should at least put your mind at ease:
- Particle physics typically requires a high-standard of evidence for discoveries ($5sigma$)
- The results at the LHC are already replicated!
- There are several detectors placed around the LHC ring. Two them, called ATLAS and CMS, are general purpose detectors for Standard Model and Beyond the Standard Model physics. Both of them found compelling evidence for the Higgs boson. They are in principle completely independent (though in practice staff switch experiments, experimentalists from each experiment presumably talk and socialize with each other etc, so possibly a very small dependence in analysis choices etc).
- The Tevatron, a similar collider experiment in the USA operating at lower-energies, found direct evidence for the Higgs boson.
- The Higgs boson was observed several datasets collected at the LHC
- The LHC (typically) publishes findings regardless of their statistical significance, i.e., significant results are not selectively reported.
- The LHC teams are guided by statistical committees, hopefully ensuring good practice
- The LHC is in principle committed to open data, which means a lot of the data should at some point become public. This is one recommendation for helping the crisis in social sciences.
- Typical training for experimentalists at the LHC includes basic statistics (although in my experience LHC experimentalits are still subject to the same traps and misinterpretations as everyone else).
- All members (thousands) of the experimental teams are authors on the papers. The incentive for bad practices such as $p$-hacking is presumably slightly lowered, as you cannot 'discover' a new effect and publish it only under your own name, and have improved job/grant prospects. This incentive might be a factor in the replication crisis in social sciences.
- All papers are subject to internal review (which I understand to be quite rigorous) as well as external review by a journal
- LHC analyses are often (I'm not sure who plans or decides this) blinded. This means that the experimentalists cannot tweak the analyses depending on the result. They are 'blind' to the result, make their choices, then unblind it only at the end. This should help prevent $p$-hacking
- LHC analysis typically (though not always) report a global $p$-value, which has beeen corrected for multiple comparisons (the look-elsewhere effect).
If anything, there is a suspicion that the practices at the LHC might even result in the opposite of the 'replication crisis;' analyses that find effects that are somewhat significant might be examined and tweaked until they decrease.
$endgroup$
2
$begingroup$
This is an excellent answer! I think it should be further emphasized how different $2sigma$ is from $5 sigma$. Using the standard $2 sigma$ conventions of social science, you have a 5% chance of getting a significant result every time you test a completely false hypothesis. (And this can easily be boosted by a factor of 10 by $p$-hacking techniques, plus you can report something like $p = 0.1$ as "trending towards significance".) Asking for $5 sigma$ is not merely being $5/2$ as rigorous, the corresponding $p$-value cutoff is roughly $0.0000003$.
$endgroup$
– knzhou
2 hours ago
add a comment |
$begingroup$
That's a really great question. The 'replication crisis' is that many effects in social sciences couldn't be reproduced. There are many factors leading to this phenomenon, including
- Weak standards of evidence, e.g., $2sigma$ evidence required to demonstrate an effect
- Researchers (subconsciously or otherwise) conducting bad scientific practice by selectively reporting and publishing significant results. E.g. considering many different effects until they find a significant effect or collecting data until they find a significant effect.
- Poor training in statistical methods.
I'm not entirely sure about the exact efforts that the LHC experiments are making to ensure that they don't suffer the same problems. But let me say some things that should at least put your mind at ease:
- Particle physics typically requires a high-standard of evidence for discoveries ($5sigma$)
- The results at the LHC are already replicated!
- There are several detectors placed around the LHC ring. Two them, called ATLAS and CMS, are general purpose detectors for Standard Model and Beyond the Standard Model physics. Both of them found compelling evidence for the Higgs boson. They are in principle completely independent (though in practice staff switch experiments, experimentalists from each experiment presumably talk and socialize with each other etc, so possibly a very small dependence in analysis choices etc).
- The Tevatron, a similar collider experiment in the USA operating at lower-energies, found direct evidence for the Higgs boson.
- The Higgs boson was observed several datasets collected at the LHC
- The LHC (typically) publishes findings regardless of their statistical significance, i.e., significant results are not selectively reported.
- The LHC teams are guided by statistical committees, hopefully ensuring good practice
- The LHC is in principle committed to open data, which means a lot of the data should at some point become public. This is one recommendation for helping the crisis in social sciences.
- Typical training for experimentalists at the LHC includes basic statistics (although in my experience LHC experimentalits are still subject to the same traps and misinterpretations as everyone else).
- All members (thousands) of the experimental teams are authors on the papers. The incentive for bad practices such as $p$-hacking is presumably slightly lowered, as you cannot 'discover' a new effect and publish it only under your own name, and have improved job/grant prospects. This incentive might be a factor in the replication crisis in social sciences.
- All papers are subject to internal review (which I understand to be quite rigorous) as well as external review by a journal
- LHC analyses are often (I'm not sure who plans or decides this) blinded. This means that the experimentalists cannot tweak the analyses depending on the result. They are 'blind' to the result, make their choices, then unblind it only at the end. This should help prevent $p$-hacking
- LHC analysis typically (though not always) report a global $p$-value, which has beeen corrected for multiple comparisons (the look-elsewhere effect).
If anything, there is a suspicion that the practices at the LHC might even result in the opposite of the 'replication crisis;' analyses that find effects that are somewhat significant might be examined and tweaked until they decrease.
$endgroup$
That's a really great question. The 'replication crisis' is that many effects in social sciences couldn't be reproduced. There are many factors leading to this phenomenon, including
- Weak standards of evidence, e.g., $2sigma$ evidence required to demonstrate an effect
- Researchers (subconsciously or otherwise) conducting bad scientific practice by selectively reporting and publishing significant results. E.g. considering many different effects until they find a significant effect or collecting data until they find a significant effect.
- Poor training in statistical methods.
I'm not entirely sure about the exact efforts that the LHC experiments are making to ensure that they don't suffer the same problems. But let me say some things that should at least put your mind at ease:
- Particle physics typically requires a high-standard of evidence for discoveries ($5sigma$)
- The results at the LHC are already replicated!
- There are several detectors placed around the LHC ring. Two them, called ATLAS and CMS, are general purpose detectors for Standard Model and Beyond the Standard Model physics. Both of them found compelling evidence for the Higgs boson. They are in principle completely independent (though in practice staff switch experiments, experimentalists from each experiment presumably talk and socialize with each other etc, so possibly a very small dependence in analysis choices etc).
- The Tevatron, a similar collider experiment in the USA operating at lower-energies, found direct evidence for the Higgs boson.
- The Higgs boson was observed several datasets collected at the LHC
- The LHC (typically) publishes findings regardless of their statistical significance, i.e., significant results are not selectively reported.
- The LHC teams are guided by statistical committees, hopefully ensuring good practice
- The LHC is in principle committed to open data, which means a lot of the data should at some point become public. This is one recommendation for helping the crisis in social sciences.
- Typical training for experimentalists at the LHC includes basic statistics (although in my experience LHC experimentalits are still subject to the same traps and misinterpretations as everyone else).
- All members (thousands) of the experimental teams are authors on the papers. The incentive for bad practices such as $p$-hacking is presumably slightly lowered, as you cannot 'discover' a new effect and publish it only under your own name, and have improved job/grant prospects. This incentive might be a factor in the replication crisis in social sciences.
- All papers are subject to internal review (which I understand to be quite rigorous) as well as external review by a journal
- LHC analyses are often (I'm not sure who plans or decides this) blinded. This means that the experimentalists cannot tweak the analyses depending on the result. They are 'blind' to the result, make their choices, then unblind it only at the end. This should help prevent $p$-hacking
- LHC analysis typically (though not always) report a global $p$-value, which has beeen corrected for multiple comparisons (the look-elsewhere effect).
If anything, there is a suspicion that the practices at the LHC might even result in the opposite of the 'replication crisis;' analyses that find effects that are somewhat significant might be examined and tweaked until they decrease.
edited 6 hours ago
answered 6 hours ago
innisfreeinnisfree
11.6k32962
11.6k32962
2
$begingroup$
This is an excellent answer! I think it should be further emphasized how different $2sigma$ is from $5 sigma$. Using the standard $2 sigma$ conventions of social science, you have a 5% chance of getting a significant result every time you test a completely false hypothesis. (And this can easily be boosted by a factor of 10 by $p$-hacking techniques, plus you can report something like $p = 0.1$ as "trending towards significance".) Asking for $5 sigma$ is not merely being $5/2$ as rigorous, the corresponding $p$-value cutoff is roughly $0.0000003$.
$endgroup$
– knzhou
2 hours ago
add a comment |
2
$begingroup$
This is an excellent answer! I think it should be further emphasized how different $2sigma$ is from $5 sigma$. Using the standard $2 sigma$ conventions of social science, you have a 5% chance of getting a significant result every time you test a completely false hypothesis. (And this can easily be boosted by a factor of 10 by $p$-hacking techniques, plus you can report something like $p = 0.1$ as "trending towards significance".) Asking for $5 sigma$ is not merely being $5/2$ as rigorous, the corresponding $p$-value cutoff is roughly $0.0000003$.
$endgroup$
– knzhou
2 hours ago
2
2
$begingroup$
This is an excellent answer! I think it should be further emphasized how different $2sigma$ is from $5 sigma$. Using the standard $2 sigma$ conventions of social science, you have a 5% chance of getting a significant result every time you test a completely false hypothesis. (And this can easily be boosted by a factor of 10 by $p$-hacking techniques, plus you can report something like $p = 0.1$ as "trending towards significance".) Asking for $5 sigma$ is not merely being $5/2$ as rigorous, the corresponding $p$-value cutoff is roughly $0.0000003$.
$endgroup$
– knzhou
2 hours ago
$begingroup$
This is an excellent answer! I think it should be further emphasized how different $2sigma$ is from $5 sigma$. Using the standard $2 sigma$ conventions of social science, you have a 5% chance of getting a significant result every time you test a completely false hypothesis. (And this can easily be boosted by a factor of 10 by $p$-hacking techniques, plus you can report something like $p = 0.1$ as "trending towards significance".) Asking for $5 sigma$ is not merely being $5/2$ as rigorous, the corresponding $p$-value cutoff is roughly $0.0000003$.
$endgroup$
– knzhou
2 hours ago
add a comment |
$begingroup$
In addition to innisfree's excellent list, there's another fundamental difference between modern physics experiments and human-based experiments: While the latter tend to be exploratory, physics experiments these days are primarily confirmatory.
In particular, we have theories (sometimes competing theories) that model our idea of how physics works. These theories make specific predictions about the kinds of results we ought to see, and physics experiments are generally then built to discriminate between the various predictions, which are typically either of the form "this effect happens or doesn't" (jet quenching, dispersion in the speed of light due to quantized space), or "this variable has some value" (the mass of the Higgs boson). We use computer simulations to produce pictures of what the results would look like in the different cases and then match the experimental data with those models; nearly always, what we get matches one or the other of the suspected cases. In this way, experimental results in physics are rarely shocking.
Occasionally, however, what we see is something really unexpected, such as the time OPERA seemed to have observed faster-than-light motion—or, for that matter, Rutherford's gold-foil experiment. In these cases, priority tends to go toward reproducing the effect if possible and explaining what's going on (which usually tends to be an error of some sort, such as the miswired cable in OPERA, but does sometimes reveal something totally new, which then tends to become the subject of intense research itself until the new effect is understood well enough to start making models of it again).
New contributor
$endgroup$
$begingroup$
I understand what you mean, but "match experimental data with models" sounds like there is ample reason to expect confirmation bias if not done properly.
$endgroup$
– Scrontch
4 hours ago
add a comment |
$begingroup$
In addition to innisfree's excellent list, there's another fundamental difference between modern physics experiments and human-based experiments: While the latter tend to be exploratory, physics experiments these days are primarily confirmatory.
In particular, we have theories (sometimes competing theories) that model our idea of how physics works. These theories make specific predictions about the kinds of results we ought to see, and physics experiments are generally then built to discriminate between the various predictions, which are typically either of the form "this effect happens or doesn't" (jet quenching, dispersion in the speed of light due to quantized space), or "this variable has some value" (the mass of the Higgs boson). We use computer simulations to produce pictures of what the results would look like in the different cases and then match the experimental data with those models; nearly always, what we get matches one or the other of the suspected cases. In this way, experimental results in physics are rarely shocking.
Occasionally, however, what we see is something really unexpected, such as the time OPERA seemed to have observed faster-than-light motion—or, for that matter, Rutherford's gold-foil experiment. In these cases, priority tends to go toward reproducing the effect if possible and explaining what's going on (which usually tends to be an error of some sort, such as the miswired cable in OPERA, but does sometimes reveal something totally new, which then tends to become the subject of intense research itself until the new effect is understood well enough to start making models of it again).
New contributor
$endgroup$
$begingroup$
I understand what you mean, but "match experimental data with models" sounds like there is ample reason to expect confirmation bias if not done properly.
$endgroup$
– Scrontch
4 hours ago
add a comment |
$begingroup$
In addition to innisfree's excellent list, there's another fundamental difference between modern physics experiments and human-based experiments: While the latter tend to be exploratory, physics experiments these days are primarily confirmatory.
In particular, we have theories (sometimes competing theories) that model our idea of how physics works. These theories make specific predictions about the kinds of results we ought to see, and physics experiments are generally then built to discriminate between the various predictions, which are typically either of the form "this effect happens or doesn't" (jet quenching, dispersion in the speed of light due to quantized space), or "this variable has some value" (the mass of the Higgs boson). We use computer simulations to produce pictures of what the results would look like in the different cases and then match the experimental data with those models; nearly always, what we get matches one or the other of the suspected cases. In this way, experimental results in physics are rarely shocking.
Occasionally, however, what we see is something really unexpected, such as the time OPERA seemed to have observed faster-than-light motion—or, for that matter, Rutherford's gold-foil experiment. In these cases, priority tends to go toward reproducing the effect if possible and explaining what's going on (which usually tends to be an error of some sort, such as the miswired cable in OPERA, but does sometimes reveal something totally new, which then tends to become the subject of intense research itself until the new effect is understood well enough to start making models of it again).
New contributor
$endgroup$
In addition to innisfree's excellent list, there's another fundamental difference between modern physics experiments and human-based experiments: While the latter tend to be exploratory, physics experiments these days are primarily confirmatory.
In particular, we have theories (sometimes competing theories) that model our idea of how physics works. These theories make specific predictions about the kinds of results we ought to see, and physics experiments are generally then built to discriminate between the various predictions, which are typically either of the form "this effect happens or doesn't" (jet quenching, dispersion in the speed of light due to quantized space), or "this variable has some value" (the mass of the Higgs boson). We use computer simulations to produce pictures of what the results would look like in the different cases and then match the experimental data with those models; nearly always, what we get matches one or the other of the suspected cases. In this way, experimental results in physics are rarely shocking.
Occasionally, however, what we see is something really unexpected, such as the time OPERA seemed to have observed faster-than-light motion—or, for that matter, Rutherford's gold-foil experiment. In these cases, priority tends to go toward reproducing the effect if possible and explaining what's going on (which usually tends to be an error of some sort, such as the miswired cable in OPERA, but does sometimes reveal something totally new, which then tends to become the subject of intense research itself until the new effect is understood well enough to start making models of it again).
New contributor
New contributor
answered 6 hours ago
chrylischrylis
1513
1513
New contributor
New contributor
$begingroup$
I understand what you mean, but "match experimental data with models" sounds like there is ample reason to expect confirmation bias if not done properly.
$endgroup$
– Scrontch
4 hours ago
add a comment |
$begingroup$
I understand what you mean, but "match experimental data with models" sounds like there is ample reason to expect confirmation bias if not done properly.
$endgroup$
– Scrontch
4 hours ago
$begingroup$
I understand what you mean, but "match experimental data with models" sounds like there is ample reason to expect confirmation bias if not done properly.
$endgroup$
– Scrontch
4 hours ago
$begingroup$
I understand what you mean, but "match experimental data with models" sounds like there is ample reason to expect confirmation bias if not done properly.
$endgroup$
– Scrontch
4 hours ago
add a comment |
$begingroup$
The paper seems to be a statistical analysis of opinions, and in no way is rigorous enough to raise a question about the LHC. It is statistics about undisclosed statistics.
Here is a simpler example for statistics of failures: Take an Olympics athlete. How many failures before breaking the record? Is the record not broken because there may have been a thousand failures before breaking it?
What about the hundreds of athletes who try to reproduce and get a better record? Should they not try?
The statistics of failed experiments is similar: There is a goal (actually thousands of goals depending on the physics discipline), and a number of trials to reach the goal, though the olympics record analogy should not be taken too far, only to point out the difficulty of combining statistics from a large number of sets. In physics there may be wrong assumptions, blind alleys, logical errors... that may contribute to the failure of reproducibility. The confidence level from statistical and systematic errors are used to define the robustness of a measurement.
from the question:
"because 50% of physics & engineering experiments aren't reproducible by the original scientists",
This is a fake statement from a dubious poll. The statistical significance of the "not reproducible " has not been checked in the poll. Only if it were a one standard deviation result , there exists almost a 50% a probability of the next trial not to reproduce.
one might expect there's a 50% chance that if the people who originally built the LHC built another LHC, they will not reach the same results
No way, because engineering and physics analysis at the LHC are over the 4 sigma level, and the probability of negation is small. Even a 3sigma level has confidence 99% , so the chance is in no way 50%.
We know the LHC results are robust because there are two major and many smaller experiments trying for the same goals. The reason there are two experiments is so that systematic errors in one will not give spurious results. We trust that the measurement statistics that give the end results are correct, as we trust for the record breaking run that the measured times and distances are correct.
(And LHC is not an experiment. It is where experiments can be carried out depending on the efforts and ingenuity of researchers, it is the field where the Olympics takes place.)
The robustness of scientific results depends on the specific experimental measurements, not on integrating over all disparate experiments ever made. Bad use of statistics. For statistics of statistics, i.e. the confidence level of the "failed experiments" have to be done rigorously and the paper is not doing that.
Another way to look at it: If there were no failures , would the experiments mean anything? They would be predictable by pen and paper.
$endgroup$
8
$begingroup$
I'm not sure I buy the Olympics analogy. Failed attempts at breaking a record isn't the same thing as a failed attempt to reproduce an experiment. It also sounds like you are saying we should just cherry pick what does work and ignore when it fails.
$endgroup$
– Aaron Stevens
7 hours ago
6
$begingroup$
You're just making it sound like if just try hard enough we can reproduce anything (break the record) , but this is not always the case. Not being able to reproduce experiment A could mean that something was wrong with experiment A and that we shouldn't try to make too many predictions (or any at all) based on experiment A. We wouldn't want to keep chasing it (trying to break the record)
$endgroup$
– Aaron Stevens
6 hours ago
3
$begingroup$
The whole concern about the replication crisis isn't that effects exist but we aren't skilled enough to reproduce them! It's that the effects didn't reproduce because they don't exist, and lots of papers are being published about effects that don't exist
$endgroup$
– innisfree
6 hours ago
2
$begingroup$
So if we must use the Olympics analogy, it's more like lots and lots of excitement about records being smashed, and it later turning out they were all heavily wind-assisted or aided by doping etc, i.e. spurious not genuine.
$endgroup$
– innisfree
6 hours ago
1
$begingroup$
I feel like this answer misses the heart of the question, which is: given that the reproducibility in physics & engineering is only 50% (and that's only if we get the people who built the LHC to do it again), how can we be sure that if we build another LHC, we will still find the Higgs boson? There are two experiments, but if I'm not mistaken, both of them use the same accelerator, so it's still conceivable that if we build another accelerator we will not see the Higgs anymore.
$endgroup$
– Allure
4 hours ago
|
show 11 more comments
$begingroup$
The paper seems to be a statistical analysis of opinions, and in no way is rigorous enough to raise a question about the LHC. It is statistics about undisclosed statistics.
Here is a simpler example for statistics of failures: Take an Olympics athlete. How many failures before breaking the record? Is the record not broken because there may have been a thousand failures before breaking it?
What about the hundreds of athletes who try to reproduce and get a better record? Should they not try?
The statistics of failed experiments is similar: There is a goal (actually thousands of goals depending on the physics discipline), and a number of trials to reach the goal, though the olympics record analogy should not be taken too far, only to point out the difficulty of combining statistics from a large number of sets. In physics there may be wrong assumptions, blind alleys, logical errors... that may contribute to the failure of reproducibility. The confidence level from statistical and systematic errors are used to define the robustness of a measurement.
from the question:
"because 50% of physics & engineering experiments aren't reproducible by the original scientists",
This is a fake statement from a dubious poll. The statistical significance of the "not reproducible " has not been checked in the poll. Only if it were a one standard deviation result , there exists almost a 50% a probability of the next trial not to reproduce.
one might expect there's a 50% chance that if the people who originally built the LHC built another LHC, they will not reach the same results
No way, because engineering and physics analysis at the LHC are over the 4 sigma level, and the probability of negation is small. Even a 3sigma level has confidence 99% , so the chance is in no way 50%.
We know the LHC results are robust because there are two major and many smaller experiments trying for the same goals. The reason there are two experiments is so that systematic errors in one will not give spurious results. We trust that the measurement statistics that give the end results are correct, as we trust for the record breaking run that the measured times and distances are correct.
(And LHC is not an experiment. It is where experiments can be carried out depending on the efforts and ingenuity of researchers, it is the field where the Olympics takes place.)
The robustness of scientific results depends on the specific experimental measurements, not on integrating over all disparate experiments ever made. Bad use of statistics. For statistics of statistics, i.e. the confidence level of the "failed experiments" have to be done rigorously and the paper is not doing that.
Another way to look at it: If there were no failures , would the experiments mean anything? They would be predictable by pen and paper.
$endgroup$
8
$begingroup$
I'm not sure I buy the Olympics analogy. Failed attempts at breaking a record isn't the same thing as a failed attempt to reproduce an experiment. It also sounds like you are saying we should just cherry pick what does work and ignore when it fails.
$endgroup$
– Aaron Stevens
7 hours ago
6
$begingroup$
You're just making it sound like if just try hard enough we can reproduce anything (break the record) , but this is not always the case. Not being able to reproduce experiment A could mean that something was wrong with experiment A and that we shouldn't try to make too many predictions (or any at all) based on experiment A. We wouldn't want to keep chasing it (trying to break the record)
$endgroup$
– Aaron Stevens
6 hours ago
3
$begingroup$
The whole concern about the replication crisis isn't that effects exist but we aren't skilled enough to reproduce them! It's that the effects didn't reproduce because they don't exist, and lots of papers are being published about effects that don't exist
$endgroup$
– innisfree
6 hours ago
2
$begingroup$
So if we must use the Olympics analogy, it's more like lots and lots of excitement about records being smashed, and it later turning out they were all heavily wind-assisted or aided by doping etc, i.e. spurious not genuine.
$endgroup$
– innisfree
6 hours ago
1
$begingroup$
I feel like this answer misses the heart of the question, which is: given that the reproducibility in physics & engineering is only 50% (and that's only if we get the people who built the LHC to do it again), how can we be sure that if we build another LHC, we will still find the Higgs boson? There are two experiments, but if I'm not mistaken, both of them use the same accelerator, so it's still conceivable that if we build another accelerator we will not see the Higgs anymore.
$endgroup$
– Allure
4 hours ago
|
show 11 more comments
$begingroup$
The paper seems to be a statistical analysis of opinions, and in no way is rigorous enough to raise a question about the LHC. It is statistics about undisclosed statistics.
Here is a simpler example for statistics of failures: Take an Olympics athlete. How many failures before breaking the record? Is the record not broken because there may have been a thousand failures before breaking it?
What about the hundreds of athletes who try to reproduce and get a better record? Should they not try?
The statistics of failed experiments is similar: There is a goal (actually thousands of goals depending on the physics discipline), and a number of trials to reach the goal, though the olympics record analogy should not be taken too far, only to point out the difficulty of combining statistics from a large number of sets. In physics there may be wrong assumptions, blind alleys, logical errors... that may contribute to the failure of reproducibility. The confidence level from statistical and systematic errors are used to define the robustness of a measurement.
from the question:
"because 50% of physics & engineering experiments aren't reproducible by the original scientists",
This is a fake statement from a dubious poll. The statistical significance of the "not reproducible " has not been checked in the poll. Only if it were a one standard deviation result , there exists almost a 50% a probability of the next trial not to reproduce.
one might expect there's a 50% chance that if the people who originally built the LHC built another LHC, they will not reach the same results
No way, because engineering and physics analysis at the LHC are over the 4 sigma level, and the probability of negation is small. Even a 3sigma level has confidence 99% , so the chance is in no way 50%.
We know the LHC results are robust because there are two major and many smaller experiments trying for the same goals. The reason there are two experiments is so that systematic errors in one will not give spurious results. We trust that the measurement statistics that give the end results are correct, as we trust for the record breaking run that the measured times and distances are correct.
(And LHC is not an experiment. It is where experiments can be carried out depending on the efforts and ingenuity of researchers, it is the field where the Olympics takes place.)
The robustness of scientific results depends on the specific experimental measurements, not on integrating over all disparate experiments ever made. Bad use of statistics. For statistics of statistics, i.e. the confidence level of the "failed experiments" have to be done rigorously and the paper is not doing that.
Another way to look at it: If there were no failures , would the experiments mean anything? They would be predictable by pen and paper.
$endgroup$
The paper seems to be a statistical analysis of opinions, and in no way is rigorous enough to raise a question about the LHC. It is statistics about undisclosed statistics.
Here is a simpler example for statistics of failures: Take an Olympics athlete. How many failures before breaking the record? Is the record not broken because there may have been a thousand failures before breaking it?
What about the hundreds of athletes who try to reproduce and get a better record? Should they not try?
The statistics of failed experiments is similar: There is a goal (actually thousands of goals depending on the physics discipline), and a number of trials to reach the goal, though the olympics record analogy should not be taken too far, only to point out the difficulty of combining statistics from a large number of sets. In physics there may be wrong assumptions, blind alleys, logical errors... that may contribute to the failure of reproducibility. The confidence level from statistical and systematic errors are used to define the robustness of a measurement.
from the question:
"because 50% of physics & engineering experiments aren't reproducible by the original scientists",
This is a fake statement from a dubious poll. The statistical significance of the "not reproducible " has not been checked in the poll. Only if it were a one standard deviation result , there exists almost a 50% a probability of the next trial not to reproduce.
one might expect there's a 50% chance that if the people who originally built the LHC built another LHC, they will not reach the same results
No way, because engineering and physics analysis at the LHC are over the 4 sigma level, and the probability of negation is small. Even a 3sigma level has confidence 99% , so the chance is in no way 50%.
We know the LHC results are robust because there are two major and many smaller experiments trying for the same goals. The reason there are two experiments is so that systematic errors in one will not give spurious results. We trust that the measurement statistics that give the end results are correct, as we trust for the record breaking run that the measured times and distances are correct.
(And LHC is not an experiment. It is where experiments can be carried out depending on the efforts and ingenuity of researchers, it is the field where the Olympics takes place.)
The robustness of scientific results depends on the specific experimental measurements, not on integrating over all disparate experiments ever made. Bad use of statistics. For statistics of statistics, i.e. the confidence level of the "failed experiments" have to be done rigorously and the paper is not doing that.
Another way to look at it: If there were no failures , would the experiments mean anything? They would be predictable by pen and paper.
edited 3 hours ago
answered 7 hours ago
anna vanna v
161k8153451
161k8153451
8
$begingroup$
I'm not sure I buy the Olympics analogy. Failed attempts at breaking a record isn't the same thing as a failed attempt to reproduce an experiment. It also sounds like you are saying we should just cherry pick what does work and ignore when it fails.
$endgroup$
– Aaron Stevens
7 hours ago
6
$begingroup$
You're just making it sound like if just try hard enough we can reproduce anything (break the record) , but this is not always the case. Not being able to reproduce experiment A could mean that something was wrong with experiment A and that we shouldn't try to make too many predictions (or any at all) based on experiment A. We wouldn't want to keep chasing it (trying to break the record)
$endgroup$
– Aaron Stevens
6 hours ago
3
$begingroup$
The whole concern about the replication crisis isn't that effects exist but we aren't skilled enough to reproduce them! It's that the effects didn't reproduce because they don't exist, and lots of papers are being published about effects that don't exist
$endgroup$
– innisfree
6 hours ago
2
$begingroup$
So if we must use the Olympics analogy, it's more like lots and lots of excitement about records being smashed, and it later turning out they were all heavily wind-assisted or aided by doping etc, i.e. spurious not genuine.
$endgroup$
– innisfree
6 hours ago
1
$begingroup$
I feel like this answer misses the heart of the question, which is: given that the reproducibility in physics & engineering is only 50% (and that's only if we get the people who built the LHC to do it again), how can we be sure that if we build another LHC, we will still find the Higgs boson? There are two experiments, but if I'm not mistaken, both of them use the same accelerator, so it's still conceivable that if we build another accelerator we will not see the Higgs anymore.
$endgroup$
– Allure
4 hours ago
|
show 11 more comments
8
$begingroup$
I'm not sure I buy the Olympics analogy. Failed attempts at breaking a record isn't the same thing as a failed attempt to reproduce an experiment. It also sounds like you are saying we should just cherry pick what does work and ignore when it fails.
$endgroup$
– Aaron Stevens
7 hours ago
6
$begingroup$
You're just making it sound like if just try hard enough we can reproduce anything (break the record) , but this is not always the case. Not being able to reproduce experiment A could mean that something was wrong with experiment A and that we shouldn't try to make too many predictions (or any at all) based on experiment A. We wouldn't want to keep chasing it (trying to break the record)
$endgroup$
– Aaron Stevens
6 hours ago
3
$begingroup$
The whole concern about the replication crisis isn't that effects exist but we aren't skilled enough to reproduce them! It's that the effects didn't reproduce because they don't exist, and lots of papers are being published about effects that don't exist
$endgroup$
– innisfree
6 hours ago
2
$begingroup$
So if we must use the Olympics analogy, it's more like lots and lots of excitement about records being smashed, and it later turning out they were all heavily wind-assisted or aided by doping etc, i.e. spurious not genuine.
$endgroup$
– innisfree
6 hours ago
1
$begingroup$
I feel like this answer misses the heart of the question, which is: given that the reproducibility in physics & engineering is only 50% (and that's only if we get the people who built the LHC to do it again), how can we be sure that if we build another LHC, we will still find the Higgs boson? There are two experiments, but if I'm not mistaken, both of them use the same accelerator, so it's still conceivable that if we build another accelerator we will not see the Higgs anymore.
$endgroup$
– Allure
4 hours ago
8
8
$begingroup$
I'm not sure I buy the Olympics analogy. Failed attempts at breaking a record isn't the same thing as a failed attempt to reproduce an experiment. It also sounds like you are saying we should just cherry pick what does work and ignore when it fails.
$endgroup$
– Aaron Stevens
7 hours ago
$begingroup$
I'm not sure I buy the Olympics analogy. Failed attempts at breaking a record isn't the same thing as a failed attempt to reproduce an experiment. It also sounds like you are saying we should just cherry pick what does work and ignore when it fails.
$endgroup$
– Aaron Stevens
7 hours ago
6
6
$begingroup$
You're just making it sound like if just try hard enough we can reproduce anything (break the record) , but this is not always the case. Not being able to reproduce experiment A could mean that something was wrong with experiment A and that we shouldn't try to make too many predictions (or any at all) based on experiment A. We wouldn't want to keep chasing it (trying to break the record)
$endgroup$
– Aaron Stevens
6 hours ago
$begingroup$
You're just making it sound like if just try hard enough we can reproduce anything (break the record) , but this is not always the case. Not being able to reproduce experiment A could mean that something was wrong with experiment A and that we shouldn't try to make too many predictions (or any at all) based on experiment A. We wouldn't want to keep chasing it (trying to break the record)
$endgroup$
– Aaron Stevens
6 hours ago
3
3
$begingroup$
The whole concern about the replication crisis isn't that effects exist but we aren't skilled enough to reproduce them! It's that the effects didn't reproduce because they don't exist, and lots of papers are being published about effects that don't exist
$endgroup$
– innisfree
6 hours ago
$begingroup$
The whole concern about the replication crisis isn't that effects exist but we aren't skilled enough to reproduce them! It's that the effects didn't reproduce because they don't exist, and lots of papers are being published about effects that don't exist
$endgroup$
– innisfree
6 hours ago
2
2
$begingroup$
So if we must use the Olympics analogy, it's more like lots and lots of excitement about records being smashed, and it later turning out they were all heavily wind-assisted or aided by doping etc, i.e. spurious not genuine.
$endgroup$
– innisfree
6 hours ago
$begingroup$
So if we must use the Olympics analogy, it's more like lots and lots of excitement about records being smashed, and it later turning out they were all heavily wind-assisted or aided by doping etc, i.e. spurious not genuine.
$endgroup$
– innisfree
6 hours ago
1
1
$begingroup$
I feel like this answer misses the heart of the question, which is: given that the reproducibility in physics & engineering is only 50% (and that's only if we get the people who built the LHC to do it again), how can we be sure that if we build another LHC, we will still find the Higgs boson? There are two experiments, but if I'm not mistaken, both of them use the same accelerator, so it's still conceivable that if we build another accelerator we will not see the Higgs anymore.
$endgroup$
– Allure
4 hours ago
$begingroup$
I feel like this answer misses the heart of the question, which is: given that the reproducibility in physics & engineering is only 50% (and that's only if we get the people who built the LHC to do it again), how can we be sure that if we build another LHC, we will still find the Higgs boson? There are two experiments, but if I'm not mistaken, both of them use the same accelerator, so it's still conceivable that if we build another accelerator we will not see the Higgs anymore.
$endgroup$
– Allure
4 hours ago
|
show 11 more comments
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4
$begingroup$
I think it is worth pointing out that the LHC doesn't just do one particle collision and then say the experiment is completed. How much do you know about what goes into such experiments, how many times they are actually repeated, and then how the data is analyzed from there?
$endgroup$
– Aaron Stevens
7 hours ago
3
$begingroup$
I was asking if you had looked into the efforts taken to make sure the results from the LHC are good results and not just mistakes. Also the LHC isn't the only particle collider in existence.
$endgroup$
– Aaron Stevens
7 hours ago
5
$begingroup$
For more about this important question than you may have bargained for, look for discussions about the "look-elsewhere effect" in the statistical analysis of the data from the mostly-independent ATLAS and CMS experiments at the LHC, especially in the context of their joint discovery of the Higgs particle.
$endgroup$
– rob♦
6 hours ago
5
$begingroup$
@Allure "Half [of scientists] have failed to reproduce their own experiments" is an enormously different statement from "half of all experiments are non-reproducible". The former statement (from the Nature article) includes scientists who have failed to reproduce a single one of their experiments, even if they successfully reproduced 99 out of 100. See page 10 of the questionnaire for the exact wording.
$endgroup$
– Chris Hayes
3 hours ago
1
$begingroup$
@ChrisHayes My thought exactly! Furthermore, a failed attempt to replicate an experiment doesn't necessarily mean that the original experiment is "non-reproducible".
$endgroup$
– jkej
2 hours ago