IRTanalyyseja

IRTanalyyseja is a Finnish term that translates to "IRT analyses" or "IRTeanlyses" in English. IRT stands for Item Response Theory, a statistical framework used in psychometrics and educational measurement. IRT analyses are conducted to understand the relationship between a person's ability or trait and their performance on a set of items, such as questions on a test or survey.

These analyses aim to estimate both the difficulty of individual items and the proficiency of individuals taking the assessment. A key feature of IRT is that it separates item parameters from person parameters. This means that the estimated ability of a person is independent of the specific set of items they answered, and the difficulty of an item is independent of the group of people who answered it.

Common applications of IRT analyses include test equating, where scores from different test forms are made comparable, and adaptive testing, where test items are selected based on a person's ongoing performance to efficiently measure their ability. IRT models, such as the Rasch model or the two-parameter logistic model, are used to mathematically describe the probability of a correct response to an item based on the person's ability and the item's characteristics. The results of IRT analyses provide valuable insights for test development, score interpretation, and understanding measurement properties.