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Posts uit juli, 2014 tonen

Developing Good Replication Practices

In my last post, I described a (mostly) successful replication by Steegen et al. of the ”crowd-within effect.” The authors of that replication effort felt that it would be nice to mention all the good replication research practices that they had implemented in their replication effort. And indeed, positive psychologist that I am, I would be remiss if I didn’t extol the virtues of the approach in that exemplary replication paper, so here goes. Make sure you have sufficient power. We all know this, right? Preregister your hypotheses, analyses, and code. I like how the replication authors went all out in preregistering their study. It is certainly important to have the proposed analyses and code worked out up front. Make a clear distinction between confirmatory and exploratory analyses. The authors did here exactly as the doctor, A.D. de Groot in this case , ordered. It is very useful to perform exploratory analyses but they should be separated clearly from the

Is There Really a Crowd Within?

In 1907 Francis Galton (two years prior to becoming “Sir”) published a paper in Nature titled “Vox populi” (voice of the people). With the rise of democracy in the (Western) world, he wondered how much trust people could put in public judgments. How wise is the crowd, in other words? As luck would have it, a weight-judging competition was carried on at the annual show of the West of England Fat Stock and Poultry Exhibition (sounds like a great name for a band) in Plymouth. Visitors had to estimate the weight of a prize-winning ox when slaughtered and “dressed” (meaning that its internal organs would be removed). Galton collected all 800 estimates. He removed thirteen (and nicely explains why) and then analyzed the remaining 787 ones. He computed the median estimate and found that it was less than 1% from the ox’s actual weight. Galton concludes: This result is, I think, more creditable to the trust-worthiness of a democratic judgment than might have been expected.  This