This paper introduces a simple, quotient effect size, termed (for 'quotient'), suitable for reporting on the effectiveness of educational interventions. The quotient effect size for a pre-test-post-test design is defined as the gain score (i.e. post-test minus pre-test) for the intervention group, divided by the gain score for the control group.…

Improving academic, behavioural, and social outcomes of students through empirical research has been a firm commitment among researchers, policy-makers, and other professionals in education across Europe and the United States (U.S.). To assist in building scientific evidences, executive bodies such as the European Commission and the Institute for…