This classic volume outlines, for both students and professionals, the mathematical theories and equations that are necessary for evaluating a test and for quantifying its characteristics. The author utilizes formulas that evaluate both the reliability and the validity of tests. He also provides the means for evaluating the reliability and validity of total test scores and individual item analysis. The work remains one of the only books on classical test theory to discuss applications, "true score" theory, the effect of test length on reliability and validity, and the effects of univariate and multivariate selection on validity.

Although originally designed as instruments to gauge students' progress, tests eventually were used to modify curricula, learning materials, pedagogy, and many practical features of schooling. Tests were employed to shape attitudes toward national issues such as employment, immigration, and defense. Worried about the enormous consequences that were at stake, advocates and opponents pitched their cases to educators, parents, journalists, and policymakers and also targeted special audiences. Testing proponents pleaded with military leaders, businesspeople, and scholastic publishers while their adversaries appealed to job seekers, college applicants, racial minorities, and anti-establishmentarians. This book illustrates how all of these parties showed interest; many became passionate; and some decisively influenced the course of American educational testing.