What does questionnaire validity measure?

Questionnaire validity is fundamentally concerned with the accuracy of the instrument in measuring what it is intended to measure. This means that it assesses whether the questions posed in a questionnaire effectively capture the concepts, behaviors, or traits that the researchers aim to investigate. When a questionnaire has high validity, it ensures that the data gathered truly reflects the underlying phenomena, leading to more reliable conclusions and insights about the subject under study.

This aspect of validity can take various forms, such as construct validity (how well the questionnaire measures the theoretical construct), content validity (the extent to which the items on the questionnaire cover the relevant content domain), and criterion-related validity (how well one measure predicts outcomes based on another measure). Overall, establishing validity is crucial for ensuring that the results derived from the questionnaire are meaningful and applicable in the context of the research objectives.