Policy evaluation determines the effectiveness and efficiency of government policies by systematically collecting and analyzing information. It aims to assess whether social interventions have achieved intended results, though results are not always well received. There are two main types of policy evaluation - formative evaluates program operations for improvement, while summative measures achievement of goals. The evaluation process involves defining the purpose and scope, specifying an appropriate design, creating a data collection plan, collecting and analyzing data, drawing conclusions, and providing feedback for program improvement. Policy evaluation uses social science research methods to examine policy effects.