Exposure to Backlit Displays Reduces Melatonin Production

the omitted cases were due to not generating enough saliva for a melatonin assay. probably not much worry of confounding there.

it doesn't prove a whole lot, if anything. we already knew that blue light suppresses melatonin, and they give the predicted effect in the study along with their measurements. annoyingly, they don't give the two-hour theoretical effect, which is the regime in which they have statistical significance in their results. neither do they formally compare the tablet-only effect to high-blue-light (enforced by goggles) effect, but it's pretty obvious that the tablet isn't as bad. which, of course, isn't surprising since the lumens are lower.

conclusion: it's an almost completely useless study, but the statistics they give seem legit enough. they don't do multiple comparisons correction, but if they did, the two-hour effect would still be significant.

look, guys, if an experiment shows a statistically significant effect which also mostly conforms to the predicted effect (and there aren't blatant design errors), then there isn't much to complain about. i could, quite likely, have done this with n=6 (two for each treatment) and still gotten significance.

Source: http://rss.slashdot.org/~r/Slashdot/slashdotScience/~3/yldh3wVREZo/exposure-to-backlit-displays-reduces-melatonin-production

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