Fourth generation evaluation represents a monumental shift in evaluation practice. The authors highlight the inherent problems faced by previous generations of evaluators - politics, ethical dilemmas, imperfections and gaps, inconclusive deductions - and blame reliance on the scientific/positivist paradigm for failure. They show how fourth generation evaluation solves persistent problems in program evaluation, comprehensively describe the differences between the positivist and constructivist paradigms of research, and provide a practical plan of the steps and processes in conducting a fourth generation evaluation.