Rasch fit statistics and sample size considerations for polytomous data.

ABSTRACT:

Background

Previous research on educational data has demonstrated that Rasch fit statistics (mean squares and t-statistics) are highly susceptible to sample size variation for dichotomously scored rating data, although little is known about this relationship for polytomous data. These statistics help inform researchers about how well items fit to a unidimensional latent trait, and are an important adjunct to modern psychometrics. Given the increasing use of Rasch models in health research the purpose of this study was therefore to explore the relationship between fit statistics and sample size for polytomous data.

Methods

Data were collated from a heterogeneous sample of cancer patients (n = 4072) who had completed both the Patient Health Questionnaire - 9 and the Hospital A

SUBMITTER: Smith AB 

PROVIDER: S-EPMC2440760 | biostudies-literature | 2008 May

REPOSITORIES: biostudies-literature