A second massive meta-analysis of the Flynn effect (norm obsolescence) was recently published (Pietschnig & Voraseck, 2015). The study investigated different Flynn effect ability domain effects (by Gf, Gc, Gv), and other moderating variables. However, the most important conclusion is that the authors conclude that the 3 IQ points per decade rule-of-thumb appears to be the best estimate of the FE on global IQ scores. This conclusion is consistent with the Trahan et al. (2014) meta-analysis and the recent AAIDD recommendation.
