Ever since accountability reforms were folded into the aid sector in the 1990s, humanitarian organizations and the larger relief system have developed and im- proved their ability to evaluate the impact of their work. Relief organizations have, in general, found it easier to measure the impact of their interventions in relation to material needs than activities geared to enhancing protection. For this reason, this scoping study asks “what works in protection and how do we know?” Three related questions will be discussed in the following order. The first is how to define humanitarian and human rights protection. The second is how to de- fine success for different types of humanitarian and human rights protection in- terventions. The third question is how to measure the impact of different protec- tion-oriented interventions.