Sensitivity and specificity of conventional and new face validation in determining the incomprehensible items by older people: Empirical evidence of testing 106 quality‐of‐life items

OBJECTIVE: This methodological research aimed to investigate and compare the sensitivity and specificity of conventional and new face validation in identifying incomprehensible items empirically. METHODS: A purposive sample of 15 older people living in three residential care homes (RCHs) in Hong Kong was used to evaluate a newly developed 106 items covering seven quality‐of‐life dimensions. The abbreviated Mental Test (Hong Kong version; AMT) was used as a screening tool for excluding those with impaired cognition. The interview was audiotaped, and incomprehensible items were identified by the research panel accordingly (served as the gold standard). The socio‐demographics of the respondents were described. Understandability (yes/no, conventional face validation method) and interpretability (4‐point Likert scale, new method) were compared and used to compute the Kappa value (representing chance agreement), sensitivity, and specificity analysis. RESULTS: Fifteen older people were interviewed and responded to the structured interview of 106 items regarding understandability and interpretability. 61 items (57%) obtained 100% positive understandability while only 35 items (33%) obtained 100% correct interpretability. The Kappa coefficient was 0.388 (P < 0.001) of the chance agreement between understandability and interpretability. The panel confirmed that 32% of items required revision (i.e., incomprehensible items). The false negative rate of using the conventional approach was up to 70.59% while both the false positive and negative rates of using the new approach were low (0%–5.88%). CONCLUSION: This empirical evidence indicated that the conventional approach of face validation for checking incomprehensible items by older people encountered a high false negative rate. On the contrary, the new approach was recommended because it demonstrated high sensitivity and specificity and low false positive and negative rates in identifying incomprehensible items.