What causes differences in achievement in Zimbabwe's secondary schools?

The authors found that students who attended high-fee-paying (trust) schools, elite urban governments schools, and mission schools scored better in mathematics and English achievement than did students in the less-well-endowed government schools and those established by local councils. Much of the variation in the student achievement was attributable to the schools the student attended. Examination results were higher in schools with a high proportion of trained teachers, with a good supply of textbooks, and with a stable faculty (high teacher retention). But once researcher control for these factors, contrary to expectations, some underendowed local council and government schools are more effective at boosting achievement than their counterparts with more resources. So, textbooks and teachers are important in raising achievement, but more research is needed into what characteristics differentiate high-achieving schools from low-achieving schools.