Thursday, February 21, 2013

Research Byte: Intro to Rasch analysis

> Title:
> An introduction to Rasch analysis for Psychiatric practice and research
> Authors:
> da Rocha, NS; Chachamovich, E; Fleck, MPD; Tennant, A
> Source:
> Abstract:
> This article aims to present the main characteristics of Rasch analysis
> in the context of patient reported outcomes in Psychiatry. We present an
> overview of the main features of the Rasch analysis, using as an example
> the latent variable of depressive symptoms, with illustrations using the
> Beck Depression Inventory. We will show that with fitting data to the
> Rasch model, we can confirm the structural validity of the scale,
> including key attributes such as invariance, local dependency and
> unidimensionality. We also illustrate how the approach can inform on the
> meaning of the numbers attributed to scales, the amount of the latent
> traits that such numbers represent, and the consequent adequacy of
> statistical operations used to analyse them. We would argue that fitting
> data to the Rasch model has become the measurement standard for patient
> reported outcomes in general and, as a consequence will facilitate a
> quality improvement of outcome instruments in psychiatry. Recent
> advances in measurement technologies built upon the calibration of items
> derived from Rasch analysis in the form of computerized adaptive tests
> (CAT) open up further opportunities for reducing the burden of testing,
> and/or expanding the range of information that can be collected during a
> single session. (C) 2012 Elsevier Ltd. All rights reserved.

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