An information-correction method for testlet-based tests is introduced. This method takes advantage of both generalizability theory (GT) and item response theory (IRT). The measurement error for the examinee proficiency parameter is often underestimated when a unidimensional conditional-independence IRT model is specified for a testlet dataset. By…

In adolescence research, the treatment of measurement reliability is often fragmented, and it is not always clear how different reliability coefficients are related. We show that generalizability theory (G-theory) is a comprehensive framework of measurement reliability, encompassing all other reliability methods (e.g., Pearson "r,"…

Recent policy has charged schools and districts with maintaining highly qualified teachers and differentiating among teachers in terms of their effectiveness (U.S. Department of Education, 2009). This emphasis has driven the development and implementation of teacher quality measures which are increasingly being used to evaluate teachers with…

The history of generalizability theory (G theory) is told from the perspective of one researcher's experiences, describing psychometric and scientific perspectives that influenced the development of G theory and its adoption. Work that remains to be done in the field is outlined. (SLD)

This study examined the difficulty level of essay topics used in the large-scale assessment of writing in relation to five different scoring models, and sought to determine what effects the scoring models would have on passing rates. In model one, examinee's score is the direct result of a score assigned by the reader or the sum of scores assigned…