Fig. 2

Path diagram showing the effects of the VPA intervention on an Executive Function (EF) latent variable. All coefficients are standardized except for the path coefficient for Group which is y-standardized (equivalent to Cohen’s d). The 95% robust (Huber-White) confidence interval (CI) is shown for the Group coefficient. The stratification variable (school gender-type, dummy coded) was included as a set of additional covariates but they are not shown in the model. The following correlations between residuals were included in the model (t₀ = pretest, t₁ = posttest): Flanker_{incon, t0} with Flanker_incon,t1 (0.34), Flanker_con,t0 with Flanker_{con, t1} (0.29), Switch_{nsw, t0} with Switch_{nsw, t1} (0.09), Flanker_{con, t0} with Flanker_{incon, t0} (0.39) Switch_{nsw, t0} with Switch_{sw, t0} (0.074), Flanker_{incon, t1} with Flanker_{con, t1} (0.41), 2-back_t1 with 2-back_t0 (0.38), but are not shown in the diagram. Abbreviations: EF = executive function, incon = incongruent, con = congruent, nsw = non-switch, sw = switch