Adjustment methods such as propensity scores and analysis of covariance are often used for estimating treatment effects in nonexperimental data. Shadish, Clark, and Steiner used a within-study comparison to test how well these adjustments work in practice. They randomly assigned participating students to a randomized or nonrandomized experiment.…

This article examines statistical issues raised when standard methods are used to analyze educable placement data to determine possible racial discrimination. An alternate approach is offered that detects disparities while avoiding the pitfalls of present methodologies. (BS)