ABSTRACT

This paper reviews recent advances that have been made in the field of theory, application of Rasch analysis. Most outcomes measures in the health care are based on an ordinal scale rather than an interval or ratio scales on the score. It's limitation is that sample-dependent, in that all statistics are confounded with the particular sample of patients who completed the assessment.Rasch analysis has been increasingly advocated and used in health care especially rehabilitation, In this analysis, the ordinal data are converted to interval scales expressed as logit. It was used to examine the overall quality of the existing instruments, and develop the new instruments. To determine if the items formed a unidimensional measure. Also, it's model implies a consistent relationship between a person's ability and item difficulty and the probability of giving a certain answer to a test item. The scale is reliable and sensitive to change during hospital rehabilitation; the scale is also a valid measure of the patient status both before and after rehabilitation programs. The Rasch analysis based on IRT provides powerful new tools to occupational therapy in rehabilitation.