Wolfgang Schneider, Bernhard Treiber

• This study addresses three themes that recur in the research on student achievement: (a) developmental modeling ofintraindividual changes in achievement over time; (b) examination of the differences among subgroups within a classroom in the determinants of achievement; (c) description of the interactions among instructional variables in determining achievement differences. Eight classrooms were preselected on the basis of their widely differing slopes obtained in a regression analysis of pre- and posttest achievement scores. MathematicsThis study addresses three themes that recur in the research on student achievement: (a) developmental modeling ofintraindividual changes in achievement over time; (b) examination of the differences among subgroups within a classroom in the determinants of achievement; (c) description of the interactions among instructional variables in determining achievement differences. Eight classrooms were preselected on the basis of their widely differing slopes obtained in a regression analysis of pre- and posttest achievement scores. Mathematics achievement differences among sixth graders were analyzed in a four-wave design and explained by aptitude and instructional variables in a structural equation framework provided by LISREL. The results demonstrate the local nature of achievement models in that neither their measurement nor structural components proved generalizable across both groups of classrooms. Mention is also made, however, of technical problems and analytical ambiguities in the interpretation of these results.…