British Educational Research Journal vol:27 issue:4 pages:407-432
This study explores the relationship between school composition and characteristics of school process and investigates their effect on mathematics achievement in Belgian (Flemish) secondary education by means of multilevel analysis. Attention is paid to the differential effectiveness of both types of school characteristics. The study confirms that there are important relationships between school composition and school process variables in secondary education. The analyses of the effect of both variables on achievement revealed that these variables have important net and joint effects on achievement independent of initial ability. We found that the addition of school composition variables to models with school process variables caused a decline in the effect of important school process variables. This outcome has important consequences for school effectiveness research, school improvement and teacher training.