Andrew Ho

The project developed and assessed a set of methods for estimating achievement gaps and their standard errors in order to address two practical problems affecting the use of achievement gap statistics: (1) the dependence of traditional gap statistics-mean differences and effect sizes-upon scaling decisions, and (2) the reporting of achievement data in categorical terms (e.g., below basic, basic, proficient, and advanced) rather than as test score results and their distributional statistics (...

State and federal educational policies are focusing increasingly on school accountability for individual student growth. As statistical models and policy approaches proliferate, little attention is paid to the serious dependency of growth statistics on the choice of the test score scale. A different score scale, defined by a nonlinear transformation of the original score scale, can theoretically alter growth statistics, reverse aggregate trends, and distort interpretations from so called val...

The purpose of this study is to develop a metric-free methodology that supports accurate cross-test comparisons of trends and gaps while taking NAEP sampling and scaling methods into account and to apply this new methodology to comparisons between NAEP and state testing program results.