A Multidimensional Rasch Analysis of the Functional Independence Measure Based on the National Institute on Disability, Independent Living, and Rehabilitation Research Traumatic Brain Injury Model Systems National Database.

A number of studies have evaluated the psychometric properties of the Functional Independence Measure (FIM™) using Rasch analysis, although none has done so using the National Institute on Disability, Independent Living, and Rehabilitation Research Traumatic Brain Injury Model Systems National Database, a longitudinal database that captures demographic and outcome information on persons with moderate to severe traumatic brain injury across the United States. In the current study, we examine the psychometric properties of the FIM as represented by persons within this database and demonstrate that the FIM comprises three subscales representing cognitive, self-care, and mobility domains. These subscales were analyzed simultaneously using a multivariate Rasch model in combination with a time dependent concurrent calibration scheme with the goal of creating a raw score-to-logit transformation that can be used to improve the accuracy of parametric statistical analyses.

The influence of equating methodology on reported trends in PISA.

In 2005 PISA published trend indicators that compared the results of PISA 2000 and PISA 2003. In this paper we explore the extent to which the outcomes of these trend analyses are sensitive to the choice of test equating methodologies, the choice of regression models and the choice of linking items. To establish trends PISA equated its 2000 and 2003 tests using a methodology based on Rasch Modelling that involved estimating linear transformations that mapped 2003 Rasch-scaled scores to the previously established PISA 2000 Rasch-scaled scores.

Translation equivalence across PISA countries.

Due to the continuous increase in the number of countries participating in international comparative assessments such as TIMSS and PISA, ensuring linguistic and cultural equivalence across the various national versions of the assessment instruments has become an increasingly crucial challenge. For example, 58 countries participated in the PISA 2006 Main Study. Within each country, the assessment instruments had to be adapted into each language of instruction used in the sampled schools.