To determine whether a behavioural intervention has worked, or not, we design trials to monitor, test and evaluate how successful a behavioural intervention was at changing behaviours.
Our evaluations are to ensure that outcomes of a behavioural intervention are attributable to the intervention itself, and that there are no alternative explanations to the changes we observe after the rollout of a behavioural intervention.
Experience tells us that many organisations need help defining the problem to begin with, so we normally recommend that organisations bring us in early to help unpack the problem.