Statistical Considerations in the Psychometric Validation of Outcome Measures

Abstract

Background The evaluation of the outcomes of total knee arthroplasty requires measurement tools that are valid, reliable, and responsive to change. However, the accuracy of any outcome measurement is determined by the validity and reliability of the instrument used. To ensure this accuracy, it is imperative that each instrument used in orthopaedics is free of biases leading to inaccurate estimates of treatment effects. Where are we now? Many patient-derived outcome instruments have been developed and tested through the application of the standard assessments that form the basis of classical test theory: validity, reliability, and responsiveness. These assessments determine if the instrument reliably measures what it is intended to measure, and if it captures differences among groups of patients or changes over time.

Translation, validation and reliability of the functional capacity questionnaire Haemophilia Activities List for haemophilia patients in Brazil

“…The reliability of the HAL‐Brazil was evaluated in this study by the ICC (test and retest between examiners 1 and 2). The inter‐examiner reliability (ICC = 0.97) and intra‐examiner reliability (ICC = 0.87) were excellent for the total HAL (values equal to or higher than 0.70 indicate a good correlation between the instruments). The high reliability suggests that the results of the instrument are reproducible over time.…”

Validation of a modified Berger HIV stigma scale for use among patients with hepatitis C virus (HCV) infection

“…Items were assigned to a factor if they loaded at �0.4 [78]. We assessed reliability by calculating the internal consistency, estimated by Cronbach α, for the scale and each subscale, with a sufficient Cronbach α �0.7 [80,81]. We investigated the absence of floor and ceiling effects, defined as 15% or more of the respondents with the lowest or highest possible score, as an estimate of content validity.…”

Odor evaluation scales for odor in neoplastic wounds: an integrative review

“…It is important to mention that evaluation instruments have been widely used for clinical practice, research, and to assist in making administrative and political decisions in many healthcare disciplines. Given this context, these evaluations can be directed towards crucial decisions concerning the effectiveness and quality of patient care, making it imperative that the scales be free of biases that can lead to inaccurate estimates (20,36) .…”

“…Hence, despite having found a considerable number of evaluation scales, the majority was not developed properly nor validated (36) . A likely reason relates to the complexity of assessing something subjective, to the familiarization with the odor and to the low number of patients with odoriferous wounds (14,20) all of these being able to justify the fact that only one scale has been validated so far.…”