Dan_Moore comments on Funnel plots: the study that didn't bark, or, visualizing regression to the null - Less Wrong

47 Post author: gwern 04 December 2011 11:05AM

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Comment author: Dan_Moore 30 November 2011 11:32:24PM 1 point [-]

I'm planning on doing a statistical study with a sample size of 21 companies. This is a financial study, and the companies chosen are the only ones that will be reporting their 2011 financial results on a certain basis necessary for the testing. (Hence the sample size.)

I'm going to do this regardless of which hypothesis is supported (the null hypothesis, my alternative hypothesis, or neither). So, I'm promising an absence of publication bias. (The null hypothesis will be supported by a finding of little or no correlation; my alternative hypothesis by a negative correlation.)

In this case, the small sample size is the result of available data, and not the result of data-mining. If the results are statistically significant and have a sizable effect, I'm of the opinion that the conclusions will be valid.

Comment author: Brickman 01 December 2011 03:03:57AM 4 points [-]

Sadly, your commitment to this goal is not enough, unless you also have a guarantee that someone will publish your results even if they are statistically insignificant (and thus tell us absolutely nothing). I admit I've never tried to publish something, but I doubt that many journals would actually do that. If they did the result would be a journal rendered almost unreadable by the large percentage of studies it describes with no significant outcome, and would remain unread.

If your study doesn't prove either hypothesis, or possibly even if it proves the null hypothesis and that's not deemed to be very enlightening, I expect you'll try and fail to get it published. If you prove the alternative hypothesis, you'll probably stand a fair chance at publication. Publication bias is a result of the whole system, not just the researchers' greed.

The only way I can imagine a study that admits that it didn't prove anything could get publication is if it was conducted by an individual or group too important to ignore even when they're not proving anything. Or if there's so few studies to choose from that they can't pick and choose the important ones, although fields like that would probably just publish fewer journals less frequently.

Comment author: TimS 01 December 2011 03:15:16AM 4 points [-]

You might find this discussion of the publication of a null result paper interesting.

Comment author: Dan_Moore 01 December 2011 03:15:52PM 2 points [-]

If I can't get this study published in the traditional way, I'll "publish" it myself on the internet.

In this case, what I'm calling the null hypothesis is somewhat meatier than a null hypothesis you would typically find in a medical study. The voluntary supplemental financial reporting for these (insurance) companies (starting with 2011) is something called market consistent embedded value (MCEV). My null hypothesis is that the phrase 'market consistent' is accurate - this is roughly equivalent to assuming that, in valuing the long-term liabilities of these companies, market participants pretend that they are securities with the same cashflows. My alternate hypothesis is that market participants value these liabilities within a framework of the company as a going concern, focusing on the company's cost of meeting these liabilities.

Comment author: garethrees 24 February 2013 01:41:54AM 2 points [-]

If I can't get this study published in the traditional way, I'll "publish" it myself on the internet.

There's always the Journal of Articles in Support of the Null Hypothesis.

Comment author: syllogism 08 December 2011 12:54:21AM 2 points [-]

If I can't get this study published in the traditional way, I'll "publish" it myself on the internet.

Where it will be only slightly more visible than a study "published" in your file drawer. I do agree you should do your best, though.

Comment author: dlthomas 08 December 2011 01:04:05AM 1 point [-]

That depends on who links to it.

Comment author: khafra 08 December 2011 05:41:27PM 1 point [-]

Yup, "Internet publishing" successfully is a combination of making it available and publicizing it; with the latter being the hard part. If you can do it well, that'd be a good thing.

Comment author: dlthomas 08 December 2011 01:07:37AM 0 points [-]

If they did the result would be a journal rendered almost unreadable by the large percentage of studies it describes with no significant outcome, and would remain unread.

This depends on how it was organized. Data sets could be maintained, and only checked when papers show interesting results in nearby areas.