There was evidence of convergent and construct validity of Physiotherapy Evidence Database quality scale for physiotherapy trials

OBJECTIVE: To evaluate the convergent and construct validity of the Physiotherapy Evidence Database (PEDro) scale used to rate the methodological quality of randomized trials in physiotherapy. STUDY DESIGN AND SETTING: PEDro total scores and individual-item scores were extracted from 9,456 physiotherapy trials indexed on PEDro. Convergent validity was tested by comparing PEDro total scores with three other quality scales. Construct validity was tested by regressing the PEDro score and individual-item scores with the Institute for Scientific Information Web of Knowledge impact factors (IF) and SCImago journal rankings (SJR) for the journals in which the trials were published. RESULTS: Testing of convergent validity revealed correlations with the other quality scales ranging from 0.31 to 0.69. The PEDro total score was weakly but significantly associated with IF and SJR (P < 0.0001). Eight of the 10 individual scale items that contribute to the PEDro total score were significantly associated with IF. CONCLUSION: This study provides preliminary evidence of the convergent and construct validity of the PEDro total score and the construct validity of eight individual scale items.