Modelling is an approach to impact evaluation which uses mathematical models to describe social and economic relationships and to infer causality from an intervention to an outcome, and/or between an outcome and its determinants. Models with more than one equation are most valuable, as they...

A randomized controlled trial (RCT) is an experimental form of impact evaluation in which the population receiving the programme or policy intervention is chosen at random from the eligible population, and a control group is also chosen at random from the same eligible population. It tests the...

Indicators provide a signal to decision makers by indicating whether, and to what extent, a variable of interest has changed. They can be used at all levels of the results framework from inputs to impacts, and should be linked to the programme’s theory of change. Most important at the lower...