WWC standards briefs provide quick, clear, and concise summaries of individual WWC standards. Each two-page brief offers an informative description and helpful graphics to clarify key concepts. Two new standards briefs discuss WWC standards for attrition (344 KB) and baseline equivalence (195 KB).

Attrition (344 KB) (loss of sample) is a common issue in education. This occurs when individuals initially randomly assigned in a study are not included in the analysis.

Baseline Equivalence (195 KB) refers to the degree to which intervention and comparison groups are similar to each other at the start of a study (baseline)—particularly, whether the groups are similar on key observable characteristics that are expected to influence participant outcomes.