Evaluation of large-scale programmes and initiatives aimed at improvement of health in countries of low and middle income needs a new approach. Traditional designs, which compare areas with and without a given programme, are no longer relevant at a time when many programmes are being scaled up in virtually every district in the world. We propose an evolution in evaluation design, a national platform approach that: uses the district as the unit of design and analysis; is based on continuous monitoring of different levels of indicators; gathers additional data before, during, and after the period to be assessed by multiple methods; uses several analytical techniques to deal with various data gaps and biases; and includes interim and summative evaluation analyses. This new approach will promote country ownership, transparency, and donor coordination while providing a rigorous comparison of the cost-effectiveness of different scale-up approaches.