A central issue in impact evaluation is supporting quick data collection and analyses while an interv ention is being rolled out to assist urgent decision-making or update know ledge of what works. This paper reviews approaches to timely evaluation that balance speed with rigour of analysis and are often combined with more standard evaluation methods. We review approaches to timely evaluation from different traditions and combine them in a conceptual framework that describes their goals, speed, and how they address complexity . Each method is paired with a case study to illustrate its value for international development evaluation research. The authors gratefully acknowledge the inputs of the following colleagues at the London School of Hygiene and Tropical Medicine who were responsible for all the background work and have published a complementary paper on this topic: Jayne Webster, Josephine Exley, James Lewis, James Copestake, Rick Davies, and James Hargreaves. We would also like to acknowledge the invaluable comments of Professor Audrey Prost and Professor Mike Clarke on an earlier version of the paper.