Again, in a comparable fashion to program evaluation, the determi-nation of the impact of a social policy involves asking questions about whether the policy has achieved its goals, whether it has worked, and if so, for whom and under what conditions. Thus, policy evaluation requires the use of both summative (measure of effectiveness) and formative (reasons for effectiveness) evaluation. Social policies often spawn what have been described as unintended, or unanticipated, con-sequences (Merton 1936).