Gough (2012) put forwards a distinction between configurative and aggregative approaches to systematic reviews. Where the first is conceived of as interpretative of different kinds of studies, the second is based on aggregated collection of data from different studies. The distinction is of a heuristic kind and is constructed in order to identify choices and potential combinations in review problematics and designs based on a set of dimensions concerning aims, approach and breadth and width, as well as structure of the review work. The kind of research that we are dealing with is not fitting within the aggregative approach. However, we have the ambition to identify research publications with a similar focus in order to analyze the possibilities for capturing research results and conclusions given this focus. In a way we are designing a review corresponding to mixed methods approach, trying to deal with configurative as well as aggregative approaches to systematic reviews. However, our ambition is not to configure the state of the art of knowledge in relation to specific interventions or possible decisions. Instead, our intention is to identify and define the potential – or the constraints and opportunities – that ILSA research offers as a research field and in translations to educational decision-making and action. It is our ambition in this systematic review containing more than 11.000 articles presenting data from international large-scale assessments (e.g. TIMSS and PISA) to analyse how the existing corpus of research constructs its objects as well as results; what are the rules and standards that are being used to identify and measure school performances, differing ways to capture effectiveness and efficiency as well as ways of ordering and classifying students and their schools and educational systems. It is our hope that this reviewing will be clarifying and of importance in order to capture results and impact of international comparisons of school results. By conducting a systematic review on international comparisons of school results we illuminate some conclusions on how to organize, perform and present the results from a systematic review, and what the limitations and frames for conducting such a review are.

Glass, G. V., & Smith, M. L. (1979). Meta-analysis of research on class size and achievement. Educational evaluation and policy analysis, 1(1), 2-16. Gough D, Oliver S, Thomas J (2013) Learning from Research: Systematic Reviews for Informing Policy Decisions: A Quick Guide. A paper for the Alliance for Useful Evidence. London: Nesta. Hacking, Ian (1992) “Style” for historians and philosophers. Studies in the History and Philosophy of Science. 23(1): pp.1-20. Popkewitz, T. (2014). Social Epistemology, the Reason of “Reason” and the Curriculum Studies. Special Issue: Nuevas Perspectivas sobre el Curriculum Escolar. Education Policy Analysis Archives DOI: http://dx.doi.org/10.14507/epaa.v22n22.2014 Prøitz, T. (2015) Metoder for systematiske kunnskapsoversikter – relevant, tilgjengelig og praktisk anvendbar? Vetenskapsrådets publikasjonsserie, forthcoming spring 2015 von Wright, G. H. (1983): Practical Reason. Blackwell von Wright, G. H. (2004). Explanation and understanding. Cornell University Press