1. A computer implemented method comprising: accessing a response model and a plurality of activities, the response model and the plurality of activities used to compute an expected business metric, wherein each of the plurality of activities has a reference value and an executed value; and computing a contribution to the business metric for each of the plurality of activities using the response model based on setting a first activity to one of the corresponding reference and executed values and setting others of the plurality of activities to the value state opposite of the first activity, wherein the computing each of the contributions is independent of a response model type.