What is the meaning of "validity" in research?

Validity in research refers to the degree to which an instrument or study accurately measures what it intends to measure. In the context of this question, it specifically addresses the accuracy of study measurements in relation to the claims being made by the researcher. If a study claims to measure a particular concept or variable, validity assesses whether the measurement truly reflects that concept or variable without being influenced by extraneous factors.

Understanding validity is crucial for ensuring that research findings are credible and can be confidently used to inform practice. For instance, if a survey claims to measure levels of anxiety but instead captures unrelated factors, it lacks validity. Consequently, all conclusions drawn from such a flawed measurement would be questionable.

Other concepts such as reliability, sample size, and subjectivity may play significant roles in research, but they do not define validity. Reliability refers to the consistency of results across different measurements, sample size impacts the generalizability of findings, and subjectivity pertains to the personal biases of participants, none of which directly address the accurate measurement aspect central to validity.