Exploring the construct validity of the Patient Perception Measure - Osteopathy (PPM-O) using classical test theory and Rasch analysis.
BACKGROUND
Evaluation of patients' experience of their osteopathic treatment has recently been investigated leading to the development of the Patient Perception Measure - Osteopathy (PPM-O). The aim of the study was to investigate the construct validity of the PPM-O.


METHODS
Patients presenting to osteopathy student-led teaching clinics at two Australian universities were asked to complete two questionnaires after their treatment: a demographic questionnaire and the PPM-O. Confirmatory factor analysis (CFA) and Rasch analysis were used to investigate the construct validity of the PPM-O.


RESULTS
Data from the present study did not fit the a-priori 6-domain structure in the CFA. Modifications to the 6-domain model were then made based on the CFA results, and this analysis identified two factors: 1) Education & Information (9 items); and 2) Cognition & Fatigue (6 items). These two factors were Rasch analysed individually. Two items were removed from the Cognition & Fatigue factor during the analysis. The two factors independently were unidimensional.


CONCLUSIONS
The study produced a 2-factor, 13-item questionnaire that assesses the patients' perception of their osteopathic treatment using the items from a previous questionnaire. The results of the current study provide evidence for the construct validity of the PPM-O and the small number of items makes it feasible to implement into both clinical and research settings. Further research is now required to establish the measures' validity in a variety of patient populations.
Centre for Chronic Disease Prevention & Management, College of Health & Biomedicine, Victoria University, Melbourne, Australia.
Jane
J
Mulcahy
Centre for Chronic Disease Prevention & Management, College of Health & Biomedicine, Victoria University, Melbourne, Australia.|Institute of Sport, Exercise & Active Living, Victoria University, Melbourne, Australia.|School of Health & Human Sciences, Southern Cross University, Lismore, Australia.
Brett
B
Vaughan