Evidence for Formative Assessment

Developments from the mid-1990s onwards, such as the work of the Assessment Reform Group and Black and Wiliam’s pamphlet Inside the Black Box (1998), have transformed the ways in which assessment is understood and used in education.

Black and Wiliam were among the first to argue for an evidence-based approach to education. Recognition of the value of using evidence-based approaches to educational interventions has resulted in a steady shift in emphasis towards using formative assessment to improve pupils’ outcomes.

Since the publication of Inside the Black Box, considerable attention has been given to formative assessment in educational research. John Hattie, Professor of Education and Director of the Melbourne Education Research Institute, is one of the most well-known proponents of evidence-based education and formative assessment.

Hattie's extensive meta-analysis of educational research was published as Visible Learning in 2008. In Visible Learning, he identifies which educational interventions are worth using in terms of their effect size. The research shows that approaches associated with formative assessment are among the techniques that have the largest effect size; they make the most difference to pupils’ outcomes.

The Educational Endowment Foundation provides an online library of research into the effectiveness of popular interventions ranked in terms of cost and effect size. This toolkit is available at:

Educational Endowment Foundation toolkiteducationendowmentfoundation.org.uk/toolkit