Test Construction & Psychometrics

Test Construction & Psychometrics

• Test Construction: The process of developing a test including defining the purpose, item writing, pilot testing, and standardization.

• Kappa Coefficient: A statistic that measures inter-rater agreement for categorical items, correcting for chance agreement.

• Kuder-Richardson Formula: A measure of internal consistency reliability for dichotomous items (e.g., KR-20, KR-21).

• Item Characteristic Curve (ICC): In item response theory, shows the probability of a correct response as a function of ability.

• Item Difficulty: The proportion of test-takers who answer an item correctly; lower values indicate harder items.

• Item Response Theory (IRT): A theory of test scoring that considers the difficulty and discriminatory power of items.

• Norm-Referenced Tests: Assessments where scores are interpreted relative to a normative sample.

• Criterion-Referenced Tests: Assessments where performance is measured against a fixed set of criteria.

• Predictor/Criterion: The predictor is the variable used to forecast another (criterion) variable.

• T-Score: A standard score with a mean of 50 and a standard deviation of 10.

• Correction for Guessing: A statistical adjustment to account for the probability of guessing answers correctly on multiple-choice tests.

• Multitrait-Multimethod Matrix (MTMM): A technique to assess construct validity using multiple traits and methods.