Applications of item response theory to non-cognitive data

PhD ceremony: Ms. I.J.L. Egberink, 13.15 uur, Academiegebouw, Broerstraat 5, Groningen

Thesis: Applications of item response theory to non-cognitive data

Promotor(s): prof. R.R. Meijer

Faculty: Behavioural and Social Sciences

Tests and questionnaires play a crucial role in psychological assessment. Both cognitive measures (e.g., intelligence tests) and non-cognitive measures (e.g., mood questionnaires, personality questionnaires) belong to the practitioner’s toolkit in different fields of psychology. Psychological measurement instruments are often used to make important decisions (e.g., school admission or personnel selection). In such cases, high-quality measurement instruments are required. Item response theory (IRT) can be of help to construct and to evaluate the psychometric quality of psychological tests and can also help researchers to improve measurement of individual persons. Although IRT originally has been used to determine the quality of cognitive tests, in recent years, the use of IRT has become more popular in the non-cognitive domain. In this thesis the use of IRT to analyze questionnaires in the non-cognitive domain is assessed. The main aim is to illustrate the usefulness of IRT for practical purposes for individual persons. The results from the different chapters show that IRT is useful to assess the psychometric qualities of psychological questionnaires, to detect and validate aberrant response patterns, to measure personality traits efficiently by means of computerized adaptive testing, and to assess preditor-criterion relations accurately by assessing differences in response scale usage at the group level.