Rasch Model

Rasch Model

Rasch models are used for analysing data from assessments to measure variables such as abilities, attitudes, and personality traits. For example, they may be used to estimate a student's reading ability from answers to questions on a reading assessment, or the extremity of a person's attitude to capital punishment from responses on a questionnaire.

Rasch models are particularly used in psychometrics, the field concerned with the theory and technique of psychological and educational measurement. In addition, they are increasingly being used in other areas, including the health profession and market research because of their general applicability.

The mathematical theory underlying Rasch models is in some respects the same as item response theory. However, proponents of Rasch models argue it has a specific property that provides a criterion for successful measurement. Application of the models provides diagnostic information regarding how well the criterion is met. Application of the models can also provide information about how well items or questions on assessments work to measure the ability or trait. Prominent advocates of Rasch models include Benjamin Drake Wright, David Andrich and Erling Andersen.