What drives the association between home chaos and school grades over time? A biometric cross-lagged panel approach

Early exposure to home chaos relates to poor school performance. This association has been found consistently in educational research, however little is known about underlying common genetic and environmental factors that might affect both constructs, thus confound the effect. Genetics explain about 60 % of variation in school performance, while (non-) shared environment constitutes the remaining variance. Also differences in home chaos – often considered an “environmental” factor – are partially influenced genetically. Thus, we investigate the effect of home chaos on school grades, while controlling for genetic and environmental confounders. We analyzed longitudinal data on school grades and home chaos in the TwinLife study (1041 twin pairs aged 11 and 13). Applying a biometric cross-lagged model allowed us to combine variance decomposition with estimating stability, correlational and cross-lagged paths while controlling for genetic and environmental confounders and strengthens the ability to draw causal inference. Results suggest that genetic confounding fully explains the effects of chaos on grades, also implying mechanisms of gene-environment interplay.