as a unified and multi-faceted concept. Under this framework, all forms of validity are connected to and are dependent on the quality of the construct. He noted that a unified theory was not his own idea, but rather the culmination of debate and discussion within the scientific community over the preceding decades. There are six aspects of construct validity in Messick's unified theory of construct validity: Consequential – What are the potential risks if the scores are invalid or inappropriately interpreted? Is the test still worthwhile given the risks? Content – Do test items appear to be measuring the construct of interest? Substantive – Is the theoretical foundation underlying the construct of interest sound? Structural – Do the interrelationships of dimensions measured by the test correlate with the construct of interest and test scores? External – Does the test have convergent, discriminant, and predictive qualities? Generalizability – Does the test generalize across different groups, settings and tasks? How construct validity should properly be viewed is still a subject of debate for validity theorists. The core of the difference lies in an epistemological difference between positivist and postpositivist theorists. Evaluation Evaluation of construct validity requires that the correlations of the measure be examined in regard to variables that are known to be related to the construct (purportedly measured by the instrument being evaluated or for which there are theoretical grounds for expecting it to be related). This is consistent with the multitrait-multimethod matrix (MTMM) of examining construct validity described in Campbell and Fiske's landmark paper (1959). There are other methods to evaluate construct validity besides MTMM. It can be evaluated through different forms of factor analysis, structural equation modeling (SEM), and other statistical evaluations. It is important to note that a single study does not prove construct validity. Rather it is a continuous process of evaluation, reevaluation, refinement, and development. Correlations that fit the expected pattern contribute evidence of construct validity. Construct validity is a judgment based on the accumulation of correlations from numerous studies using the instrument being evaluated. Most researchers attempt to test the construct validity before the main research. To do this pilot studies may be utilized. Pilot studies are small scale preliminary studies aimed at testing the feasibility of a full-scale test. These pilot studies establish the strength of their research and allow them to make any necessary adjustments. Another method is the known-groups technique, which involves