Which method can improve the reliability of questionnaires?

Implementing test-retest reliability is a method that significantly enhances the reliability of questionnaires. Test-retest reliability involves administering the same questionnaire to the same group of people at two different points in time and then comparing the scores. This approach assesses the consistency of responses over time, ensuring that the results are stable and reliable if the underlying construct being measured has not changed. A high correlation between the two sets of responses indicates that the questionnaire consistently measures what it is intended to over time, thereby confirming its reliability.

In contrast, other methods may not directly enhance reliability in the same way. For example, using open-ended questions can provide rich qualitative data but may introduce variability in responses that can make it harder to attain consistent results. Limiting the number of questions might streamline a questionnaire, but it doesn't address the inherent consistency of responses over time. Finally, using informal interviews can gather valuable information but does not utilize the structured format of a questionnaire, which can complicate the measurement of reliability. Thus, implementing test-retest reliability stands out as an effective strategy for improving questionnaire reliability.