Everyone is talking impact nowadays. Organisations can’t get away anymore with just reporting about a few outputs, such as the number of people they have reached or the number of schools they have built. Nowadays, they also need to understand, report about and be accountable for the change (both positive and negative) that is created by their activities. Did the intervention actually make a lasting difference in people’s lives? Since such results generally only occur after a longer period of time, sometimes even years after a programme or intervention was initiated, measuring impact can be challenging. Especially determining to what extent your intervention contributed to the change may be a tough task. How much of the results can you claim? And how do you calculate your impact claim?