Max Primbs

@maxprimbs.bsky.social

2417 Followers 229 Following

PhD Student, Radboud University (Netherlands). Researching how social and cultural environments shape attitudes. Big Team Science & Statistics enthusiast.

To further illustrate the claim that small effects can be consequential in large samples or at the population level, Götz et al. (2022) presented the correlation between aspirin and the prevention of heart attacks (r = .03). Ferguson (2009) pointed out the flaw in using this effect size to make the generalized argument that small effects matter through an analogy with wearing a bulletproof vest: The effect size of wearing a bulletproof vest on the probability of dying is large if we examine people who get shot but very small if we include the millions of people who never get shot. Likewise, the causal effect of aspirin on the chance of a heart attack is substantial, but there is only a small effect in the reduction of heart attacks if a large group of people, many of which would never suffer a heart attack, regularly take aspirin. The important difference between medicine and psychology is that in psychology researchers rarely include a large majority of individuals in their studies that are not expected to benefit from an intervention. For example, when we examine the effectiveness of a new treatment for depression, we usually do not conduct the study on a sample in which only a small minority of individuals are depressed. Therefore, when a small effect is observed in psychology, it may not matter at the population level, and any claims of why it would matter need to be theoretically justified and/or empirically supported.