Validiuden

Validiuden, understood as the concept of validity, is the degree to which a measurement, claim, or inference accurately reflects the thing it is intended to represent. It is a central concern across disciplines such as research methodology, psychology, philosophy, and law, where the quality of conclusions depends on validity as well as other factors like reliability.

In research, validity is often discussed in several overlapping forms. Measurement validity concerns how well a test or instrument captures the intended construct. Content validity assesses whether the instrument covers the full domain of the construct. Criterion validity looks at how well the instrument correlates with external criteria, including concurrent and predictive validity. Construct validity evaluates how well the instrument relates to other measures as theory predicts, incorporating evidence of convergent and divergent validity. Internal validity refers to causal conclusions within a study being free from confounding variables, while external validity concerns the generalizability of findings to other settings, populations, or times. Statistical validity concerns the correctness of inferences drawn from data, given the design and analysis.

In logic, validity describes the structure of an argument: if the premises are true, the conclusion must be true. This is distinct from the truth of the premises themselves. Inductive reasoning speaks of strength or cogency rather than strict validity.

Reliability and validity are related but not identical; a measurement can be reliable without being valid, and valid measurements typically require reliability. Improving validiuden often involves careful study design, rigorous instrument development, and critical appraisal of evidence through triangulation and replication.