Review article
New psychometric strategies for an appropriate selection and use of outcome measures in physical and rehabilitation medicine
Franco FANCIGNONI
; School of Specialization in Physical and Rehabilitation Medicine, Tor Vergata University, Rome, Italy
Giorgio FERRIERO
; Department of Physical Medicine & Rehabilitation, Hamad Medical Corporation, Doha, Qatar
Marcella OTTONELLO
; Department of Physical & Rehabilitation Medicine, Salvatore Maugeri Foundation, Clinica del Lavoro e della RiabilitazioneIRCCS, Nervi (GE), Italy
Abstract
In order to be useful for their intended purposes, outcome measures (rating
scales and questionnaires) must provide information that allows valid inferences
and decisions to be made.
Basic classical test theory is still widely used in peer-reviewed, indexed journals
for validating these tools. Classical test theory methods mainly focus on an
instrument’s total score, whichis simply asserted as the relevant statistic. But,
this approach neglects a series of criteria that need to be considered when evaluating the psychometric properties of a measurement tool, and that can
be analysed by Rasch analysis. The validation activities performed by RA are
numerous; the most important ones are those connected with the analysis of:
a. dimensionality;
b. functioning of rating scale categories;
c. internal construct validity of the measure;
d. reliability of the scale, in terms of ‘separation’ (i.e. the ratio of the true
spread of the measures with their measurement error).
Thus, RA is being increasingly used in the development and evaluation of
clinical tools for health care.
The purpose of the present paper is to describe the main features of Rasch
analysis in assessing outcome measures, and summarize some results of our
recent psychometric studieson outcome measures in Physical and Rehabilitation
Medicine, in order to provide insights for the appropriate selection and use of
outcome measures.Physiatrists have a responsibility to ensure that measures
used in clinical settings are psychometrically sound, and that they are
administered thoughtfully and analysed correctly. The contents of this article
can bring the final users to critically inspect each outcome measure and the
related literature before adopting it for clinical practice, decision making, or
policy development.
Keywords
outcome measure; Rasch analysis; psychometrics; Physical and Rehabilitation Medicine
Hrčak ID:
163324
URI
Publication date:
3.4.2016.
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