How is validity defined in evaluation research?

Validity in evaluation research is fundamentally about ensuring that the tool or instrument used effectively captures the concept it aims to measure. When it is stated that validity is "the degree to which an instrument measures what it intends to measure," it emphasizes the importance of aligning measurement with the intended construct or outcome. For example, if a survey is designed to measure educational achievement, validity would ensure that the survey actually reflects various dimensions of educational success and not confounding variables.

This definition is central to evaluation research because high validity increases the confidence that any conclusions drawn from the data are accurate representations of the phenomena being studied. It is critical for researchers to assess and ensure validity in their measures to support credible findings and effective decision-making based on those findings.

In contrast, aspects like stakeholder engagement, data reliability, and overall impact are important for different reasons in evaluation but do not define the concept of validity itself. These elements supplement the core concept but do not encapsulate what validity entails.