To support and promote secondary analyses, the International Association for the Evaluation of Educational Achievement (IEA) is making the SITES 2006 international database and accompanying User Guide available to researchers, analysts, and public users. The database comprises national contexts and school- and teacher-level data from 23 education…

Rules are given for estimating accuracy of predictions based on a multiple regression equation. Formulas for moments of distribution and other parameters are noted. The approximate inflation in mean absolute error due to estimating the regression coefficients is a function of the base sample size and number of predictors. (DWH)

Direct and indirect effects in decomposed zero-order correlations among variables in causal models are considered. Under certain circumstances, the components of the decompositions could be interpreted as direct, indirect, and spurious causal effects, plus a component called joint associations. The sum of the direct and indirect effects is the…