The 'impact evaluation’ theme at the Centre for Evaluation brings together researchers from the London School of Hygiene & Tropical Medicine and partner organisations who specialise in evaluations assessing and quantifying the impact of complex interventions. Members are involved in all stages of evaluation, including its design, conduct, analysis, and/or reporting. 

Members of the theme utilise a range of methods to evaluate the ‘impact’ of complex policies and interventions on health or different determinants of health. Impact evaluations aim to ask causal questions: did a particular event, policy change, or intervention cause a change in outcomes for the people who experienced the intervention? 

The impact evaluation study designs (described below) use a range of statistical tools to establish causal inference, or to be as certain as possible that the intervention, and not another activity or trend, caused the change.