The data collection of a cohort study requires making many decisions. Each decision may introduce error in the statistical analyses conducted later on. In the present study, a procedure was developed for estimation of the error made due to the composition of the sample, the item selection procedure, and the test equating process. The math results…

The central question in this study is whether the language and math delays of the different socio-economic and ethnic minority groups targeted by Dutch educational disadvantage policy have diminished or not. Data are from the years 1995, 1999, 2003 and 2008. Information from a total of 90,000 pupils in Grades 2 and 8 was selected to represent the…

An outline is given of the context in which The International School Effectiveness Research Project (ISERP) was designed and it is argued that the deficiencies of existing studies and the increased internationalization of education makes the more rigorous approach of ISERP essential. A number of methodological lessons from the study are given,…