Content Validity Evidences: Theoretical Advances and Estimation Methods

Abstract

The purpose of this paper has been to carry out a review of the historical evolution of one aspect of test validity - content validity - as well as to expose some of the most popular methods used for its evaluation. The concept of content validity has undergone many modifications from its inception to the present time. However, in the past these changes have focused on which pieces of evidence must be presented and the different statistical methods used to study it, while keeping its meaning essentially stable over time. Nowadays, evidence for content validity is considered necessary (though not the sole factor) for interpreting test results. Finally, the use of both qualitative and quantitative methods is recognized as the best procedure for performing an in-depth study of content validity. Regarding the former, this paper recommends the IVC index because, besides being currently the most used, it shows the most benefits when compared to the alternatives proposed over the years. Regarding the latter, the Generalizability Theory is understood as the most comprehensive and accurate procedure for measuring this aspect of test validity.