The School Mix Effect: a Study of the Likely Effect of School Social Class Composition on School Processes and Student Achievement in Four New Zealand Schools

Abstract

The idea of a contextual effect of the social class composition of a school's intake on individual student performance - the school mix effect - has been debated in quantitative school effectiveness literature for many years. However its existence has remained a matter of speculation. I review research since the 1960s to point to political, ideological and methodological reasons for the current ignorance of the effects of school mix on student achievement. The review suggests there is a prima facie case that the effect does exist. Given the limitations of past studies, I argue that micro-level qualitative research to find possible causal mechanisms will be the most useful approach for further research. Another review of quantitative and qualitative literature suggests five hypotheses with respect to the likely causes of the effect. These are: (i) there is no effect; (ii) the effect is caused by reference group processes; (iii) the effect is caused by instructional processes; (iv) the effect is caused by organisational and management processes; and (v) the effect is a whole school effect incorporating all of (ii) - (iv) above. Empirical research in four New Zealand secondary schools with different and similar socio-economic mixes was carried out to investigate these hypotheses. Due to the stubborn causal issues at the heart of the effect, the research was necessarily limited to investigating whether conditions existed in the schools to support the effect. The research focussed on the experiences of matched working class 'ordinary kids' and used nested and comparative school case studies drawing on multiple data sources. Evidence was found to support a whole school explanation for the school mix effect stemming from the cumulative effects of reference group, instructional and organisational/management processes. A number of implications are drawn for research and policy. In particular, the study suggests the need for a more contextualised approach to assessing school effectiveness and accountability. The study also implies that if the social class mix of school intakes become increasingly polarised through neo-liberal policies of choice and competition in education, disparities between student outcomes in high and low socio-economic schools will intensity also.