To understand why variations in cost and performance are occurring, councils work together to ‘drill-down’ into the benchmarking data across service areas. This process has been organised around ‘family groups’ of councils so that we are comparing councils that are similar in terms of the type of population that they serve (e.g. relative deprivation and affluence) and the type of area in which they serve them (e.g. urban, semi-rural, rural). The point of comparing like with like is that this is more likely to lead to useful learning and improvement.