4 ms·

Studies with low significance are no better than anecdotes.

stdbrouw 9y ago
This is not true at all. Small studies are simply less accurate. Would you prefer to conduct further research on a cure for cancer that's been shown to lead to recovery in 0-50% of cases (the confidence interval includes 0%, so not significant) or in .5-1% of cases (significant)?
- Will_Parker 9y ago
  How does it make sense to suppose it could lead to recovery in 50% of cases, if a drug that does nothing has a 5% chance of producing the same result in your study?
  - stdbrouw 9y ago
    Because it has a 95% chance of producing a different (better) result. Statistics is all about the quantification of uncertainty.
- imh 9y ago
  As a matter of fact, I can do even better than 0-50% of cases! Consuming widgets has been shown to lead to recovery in 0-100% of cases! It isn't as simple as you suggest.
  - stdbrouw 9y ago
    Yep, and that makes widgets a more interesting target for follow-up studies than a treatment that has been shown to result in no clinically significant improvement. It really is that simple.
- Klockan 9y ago
  Surely we could create a system to fund extensions of studies with promising initial results? I just think that it is dangerous to call 95% significant.
csours 9y ago
https://xkcd.com/552/ https://xkcd.com/552/ Alt-Text: "Correlation doesn't imply causation, but it does waggle its eyebrows suggestively and gesture furtively while mouthing 'look over there'." I think you could replace correlation with "small studies" or "anecdotes". These are all things that suggest there may be some effect, and there may be merit in further study.
- Klockan 9y ago
  I agree that anecdotes are useful, I disagree with publishing them in scientific journals and telling the public that we found significant results.
xelxebar 9y ago
Well, Bayes theorem should let us, in theory, combine several small studies into the equivalent of one larger one. I'm practice it's harder than simple number crunching due to methodological differences between studies, but it seems a shame to call a study essentially worthless. I like to be a little optimistic and think, "Data is data and data is good. The challenge is in interpreting it."
- _dps 9y ago
  > "Data is data and data is good" This is a reasonable intuition, but is hard to square with the increased risk of publication bias for small studies (i.e. we should question whether the typical small study published is really "data" in the sense we'd like). Since small studies are more sensitive to noise and "fishing" for an effect, and since non-results are rarely published, what happens with meta-analysis of many published small studies is that you end up primarily looking at outliers rather than typical results. Since most research questions have a directionality to what counts as "interesting", the outliers also tend to be clustered on one side rather than evenly split. The two papers I recommend anyone read if they care about these problems are: Why Most Published Research Findings are False http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0020124 http://journals.plos.org/plosmedicine/article?id=10.1371/jou... The garden of forking paths: Why multiple comparisons can be a problem, even when there is no “fishing expedition” or “p-hacking” and the research hypothesis was posited ahead of time http://www.stat.columbia.edu/~gelman/research/unpublished/p_hacking.pdf http://www.stat.columbia.edu/~gelman/research/unpublished/p_...
- Klockan 9y ago
  There is plenty of evidence that people who recreate results often tries until they get the same result as the original paper. For example a scientist made a mistake when counting the number of chromosomes and reported that humans had 48, a number that was replicated for over 30 years. In this case it would obviously have been better if the original paper was never published. https://www.ncbi.nlm.nih.gov/pubmed/16463025 https://www.ncbi.nlm.nih.gov/pubmed/16463025
czep 9y ago
That's true 95% of the time.
- Klockan 9y ago
  Do you believe that 95% of studies proving that humans possess paranormal abilities are true?

This is not true at all. Small studies are simply less accurate. Would you prefer to conduct further research on a cure for cancer that's been shown to lead to recovery in 0-50% of cases (the confidence interval includes 0%, so not significant) or in .5-1% of cases (significant)?

Will_Parker 9y ago
How does it make sense to suppose it could lead to recovery in 50% of cases, if a drug that does nothing has a 5% chance of producing the same result in your study?
- stdbrouw 9y ago
  Because it has a 95% chance of producing a different (better) result. Statistics is all about the quantification of uncertainty.
imh 9y ago
As a matter of fact, I can do even better than 0-50% of cases! Consuming widgets has been shown to lead to recovery in 0-100% of cases! It isn't as simple as you suggest.
- stdbrouw 9y ago
  Yep, and that makes widgets a more interesting target for follow-up studies than a treatment that has been shown to result in no clinically significant improvement. It really is that simple.
Klockan 9y ago
Surely we could create a system to fund extensions of studies with promising initial results? I just think that it is dangerous to call 95% significant.

csours 9y ago

https://xkcd.com/552/ https://xkcd.com/552/ Alt-Text: "Correlation doesn't imply causation, but it does waggle its eyebrows suggestively and gesture furtively while mouthing 'look over there'." I think you could replace correlation with "small studies" or "anecdotes". These are all things that suggest there may be some effect, and there may be merit in further study.

Klockan 9y ago
I agree that anecdotes are useful, I disagree with publishing them in scientific journals and telling the public that we found significant results.

xelxebar 9y ago

Well, Bayes theorem should let us, in theory, combine several small studies into the equivalent of one larger one. I'm practice it's harder than simple number crunching due to methodological differences between studies, but it seems a shame to call a study essentially worthless. I like to be a little optimistic and think, "Data is data and data is good. The challenge is in interpreting it."

_dps 9y ago
> "Data is data and data is good" This is a reasonable intuition, but is hard to square with the increased risk of publication bias for small studies (i.e. we should question whether the typical small study published is really "data" in the sense we'd like). Since small studies are more sensitive to noise and "fishing" for an effect, and since non-results are rarely published, what happens with meta-analysis of many published small studies is that you end up primarily looking at outliers rather than typical results. Since most research questions have a directionality to what counts as "interesting", the outliers also tend to be clustered on one side rather than evenly split. The two papers I recommend anyone read if they care about these problems are: Why Most Published Research Findings are False http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0020124 http://journals.plos.org/plosmedicine/article?id=10.1371/jou... The garden of forking paths: Why multiple comparisons can be a problem, even when there is no “fishing expedition” or “p-hacking” and the research hypothesis was posited ahead of time http://www.stat.columbia.edu/~gelman/research/unpublished/p_hacking.pdf http://www.stat.columbia.edu/~gelman/research/unpublished/p_...
Klockan 9y ago
There is plenty of evidence that people who recreate results often tries until they get the same result as the original paper. For example a scientist made a mistake when counting the number of chromosomes and reported that humans had 48, a number that was replicated for over 30 years. In this case it would obviously have been better if the original paper was never published. https://www.ncbi.nlm.nih.gov/pubmed/16463025 https://www.ncbi.nlm.nih.gov/pubmed/16463025

czep 9y ago

That's true 95% of the time.

Klockan 9y ago
Do you believe that 95% of studies proving that humans possess paranormal abilities are true?