Identification of a Flynn Effect in the NLSY: Moving from the center to the boundaries

Using Item Response Theory to assess the Flynn Effect in the National Longitudinal Study of Youth 79 Children and Young Adults data

“…When all age groups were averaged, this study found that on both the PPVT-R and the PIAT-Math, the raw scores, standard scores, and percentile scores showed an increase in score performance over time. This result is confirmed by Rodgers and Wanstrom (2007), who found a FE in the same data (using regression methods) before adjusting for mother's IQ score. When using IRT-based scores, however, an increase in scores was also found, but was much smaller and, at least for the PPVT-R, a very negligible increase.…”

The reproduction of intelligence

“…However, recent results show that this rising trend, known as the Flynn effect, is either diminishing or reversing in the most advanced societies. A marginal Flynn effect was still observed among children born between 1973 and 1995 in the United States (Rodgers & Wänström, 2007), most recent trends in Britain are ambiguous (Flynn, 2009;Shayer, Ginsburg & Coe, 2007), and military conscripts born after about 1980 in Denmark (Teasdale & Owen, 2008) and Norway (Sundet, Barlaug & Torjussen, 2004) show stagnating intelligence or a slow decline.…”

An Investigation of Growth Mixture Models for Studying the Flynn Effect

“…First, FE scholarship should seek to gather data across multiple time periods. While there are some exceptions (e.g., [14,72,73]), most FE work only collects data from two time periods. The minimum number of time periods needed for a latent curve model is three, but four or more is better [17]; the same applies for GMMs.…”