New digital feature editorship at the Psychonomic Society

As of January 1, 2016, I am the new methods editor for the Psychonomic Society digital features. Steve Lewandowsky has written an introductory post with a bit of background, and my first post -- about Arsenault and Buchsbaum's recent article in Psychonomic Bulletin & Review on neuroimaging evidence for motor theories of speech -- is up as well.

• "From Bach to Bayes and Wales: the Richard Morey challenge" (by Steve Lewandowsky)
• "In the mind's ear: No connection between hearing and speaking in motor cortex" (my first post)

Asymmetric funnel plots without publication bias

In my last post about standardized effect sizes, I showed how averaging across trials before computing standardized effect sizes such as partial \(\eta^2\) and Cohen's d can produce arbitrary estimates of those quantities. This has drastic implications for meta-analysis, but also for the interpretations of these effect sizes.  In this post, I use the same facts to show how one can obtain asymmetric funnel plots — commonly taken to indicate publication bias — without any publication bias at all. You should read the previous post if you haven't already.

Averaging can produce misleading standardized effect sizes

Recently, there have been many calls for a focus on effect sizes in psychological research. In this post, I discuss how naively using standardized effect sizes with averaged data can be misleading. This is particularly problematic for meta-analysis, where differences in number of trials across studies could lead to very misleading results.