The concepts of cause and effect are critical to the field of program evaluation. Experimentally-designed evaluations--those that randomize to treatment and control groups--offer a convincing means for establishing a causal connection between a program and its effects. Experimental Evaluation Design for Program Improvement considers a range of impact evaluation questions, particularly those questions that focus on the impact of specific aspects of a program. Laura R. Peck shows how a variety of experimental evaluation design options can provide answers to these questions, and she suggests opportunities for experiments to be applied in more varied settings and focused on program improvement efforts.