This guide highlights some of the key challenges with current models of evaluation, and introduces the retrospective matched control study design. It then outlines ten steps towards retrospective matching in order to evaluate new health and care service models, which evaluators can build on. These are: clarify the aims of the service and the evaluation; decide on the number of people needed to demonstrate an effect; ensure permission is granted to access person-level datasets; ensure there are data on who received the new services, and some information about the service received; identify the potential control population; create longitudinal patient-level histories of service use; identify matched controls; monitor outcome variables for those receiving the new service and matched controls; undertake summative analysis; and continuously monitor. The guide also sets out an example of how one area is working towards using retrospective matched control study designs in local evaluations. This guide is aimed at those involved in the evaluation of service redesign at a local, regional or national level, including health and care analysts, statisticians, public health professionals, commissioners and others with an interest in evaluating new models of care. The model may be used in a range of initiatives such as the Better Care Fund, Integration Pioneers, the Prime Minister’s Challenge Fund and those emerging from NHS England’s Five Year Forward View.