The NFER blog

Evidence for excellence in education


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RCTs in schools: making the case for ‘fair tests’

By guest blogger Ben Styles, Research Director

When we were at school we learned the concept of a ‘fair test’; the notion that if we wanted to discern the effect of something, we need to keep everything constant apart from the thing we are testing. Historically, for much of the research into effectiveness of classroom interventions, this simple idea has not been adhered to.  Groups of students who received the intervention have been compared to others who cannot be regarded as equivalent, or in some cases there has been no comparison group at all. Continue reading