Variance explained is mostly bad
Reporting the proportion of variance explained by some statistical model is ubiquitous. However, just like p-values, it is a misleading metric. I'll try explain why it is used, and why…
African IQs using only age heaping data
Age heaping is a fascinating method. I blogged about it back in 2015, hoping that someone would take up the idea of fusing this literature from historical economics with modern…
The signal and the noise in meta-analysis
OK, it has been written about already by some others, but I also want to talk about this John Protzko pile-on: https://twitter.com/JProtzko/status/1554112968245137408 Here's the original plot in case the tweet…
R for machine learning and other stuff
One of the best things about R is that there is a never-ending stream of new short textbooks being written. Most of these are now written using the neat bookdown…
p > .05 thus no effect thus familial confounding fallacies
Reading over some sibling control studies, BIG TOUGH GUY mentioned this quite wrong study: Meier, S. M., Mors, O., & Parner, E. (2017). Familial confounding of the association between maternal…
Review: Psychological Testing: Theory and Practice (Colin Cooper)
Cooper, C. (2018). Psychological testing: theory and practice. Routledge. This is a pretty food good introduction to psychometrics (the science of psychological measurement). There is the now customary dislike for…
Self-teaching stats with R in 2020
See 2019 post on introductions to psychology etc. for broader coverage Anon asks me today: What would be the best way to quickly self-teach enough statistics to be able to…
Lynn’s impossible regression values: bounded outcome variables with OLS
Someone emails me: Hello Mr. Kirkegaard, This is a question I emailed to Richard Lynn about data in regression analysis in his book Intelligence that did not make sense to…
Data imputation in psychometric meta-analysis
Yep, it's another comment based on reading too much industrial and organizational psychology! The Schmidt and Hunter approach to meta-analysis, AKA validity generalization theory (VG theory) AKA psychometric meta-analysis (PMA)…
Interrater reliability in job performance ratings
And now for something completely different. Well, not that different. But not the usual things. I've been working in human resources/education since February. It's quite enjoyable work. My job consists…