beautiful things happen when people make their data publicly available.
from 1895 to 1903, one anonymous man kept track of his nocturnal emissions every day.* in 1904, he published an analysis of seasonal effects in his eight years of data. because few statistical techniques had been invented for analyzing these types of data, the author based his conclusions mainly on a visual examination of the data (see top panel of the figure below). he concluded that his nocturnal emissions were higher in the spring and summer than in fall and winter.
the author also did something else impressive: he shared the raw data with the world (in numerical form, not the actual biological specimens). in 2012, widaman and helm** decided to reanalyze the data with six different modern quantitative techniques. i won't get into the details of their analyses,*** but even just rescaling the y-axis and adding 95% confidence intervals to the monthly averages (bottom panel below****) shows just how weak the evidence was for the author's conclusion that there were seasonal patterns in the data. indeed, widaman and helm's re-analyses did not show much evidence of any monthly or seasonal patterns at all.
the authors describe their results as anticlimactic,***** because their main conclusion is a null effect for seasonality. however, i would argue that the ability to reanalyze 100+ year-old data is quite titillating. it is a striking demonstration of the great strides we've made in quantitative methods in the last 110 years, and a vivid example of how data sharing enables self-correction in science.
sometimes, sharing your data can feel like giving away your most intimate possession, a piece of yourself. in anonymous' case, that was kind of true. but if you try it a couple times, you soon realize that, most of the time, sharing your data is not a form of self-exposure - nothing bad happens, no one is pointing and laughing. most of the time, no one is going to pay any attention at all. but if they do, chances are, something good will come out of it.
when it comes to data sharing, there's no such thing as TMI. anonymous was brave enough to do it back in 1904, with his most intimate data. i think it's time for the rest of us to be as open and transparent as anonymous.******
give science a present this holiday season, share your data.
* that's what i call within-person data.
** full disclosure: helm is my boyfriend. in case it's not obvious, this paper played a critical role in our courtship.
*** because i don't understand them.
**** july 1897 was an exciting month for anonymous.
***** in case this makes you think it's not a serious paper, i'll have you know there is one equation in there with six different greek letters.
****** or, you know, maybe a tiny bit less open.
Anonymous (1904). Nocturnal emissions. American Journal of Psychology, 15, 104-107.
Widaman, K. F., & Helm, J. L. (2012). Nocturnal emissions: A failure to replicate. American Journal of Psychology, 125, 39-50.