When it comes to formulating or implementing public policies, programmes and projects, a series of decisions are taken. *The quality of our decisions determines the success or failure of our projects, the performance of our governance, etc*. As a result, decisions need to be well thought through before they are taken. This raises the question of "what should underpin our decisions: evidence or opinion? When should we compromise and when shouldn't we? During this 3rd quarter webinar, the Institut Africain de Suivi et Évaluation d'Impact des Politiques Programmes et Projets de Développement has invited 2 communicators to introduce you to the techniques and practices used in decision-making.