The “decline effect” refers to scientific effects that appear to decrease in magnitude as more studies are conducted. For instance, early studies of some phenomenon might report large differences between treatment and control means, but later studies report small differences or no difference. Decline effects might arise because of publication bias, regression to the mean, and changes over time in true effect sizes. Reviews in ecology and other fields suggest that decline effects are common (for ecology see Jennions & Møller 2002, Barto & Rillig 2012).
Question: what should you call the opposite of a decline effect? And do you know of any examples?
No, I’m not being contrarian for the sake of being contrarian, I have a reason for asking. As I said in my talk at #ESA2020, I have reason to think that, in ecology, decline effects are no more common than, um, whatever the opposite of a decline effect is. So I want to know about any other reports of the opposite of a decline effect. Whether anecdotal, or from systematic reviews.
Just off the top of my head, it seem like heath effects of air pollution might be an example? I’m no expert, all I know is what I read in the news, but recent estimates seem to suggest that air pollution is worse for us than we used to think it was.