Advantages of the Rasch measurement model in analysing educational tests: an applicator's reflection

Educational achievement is a very important issue for parents, teachers, and the government. An accurate measurement plays a very important role in evaluating achievement fairly, and, therefore, analysis methods have been developed considerably in recent years. Education based on long-time learning processes forms a fruitful base for item tests, as it opens up possibilities to design a nearly unlimited number of items. There are several methods available to analyse such tests, but which method is the most useful and in which situation? The Rasch measurement from the Institute for Object Measurement (IOM) has pointed out to be the most useful in evaluating individual items and their functioning in a test. While the Rasch model gives a great deal of information about each single item on a test, the classical item analysis can provide additional information about response alternatives. Multiparametric item response theory (IRT) models can also provide some additional information about items, but those models require careful interpretation of results.