Impact evaluation designs vary based on the goals of the study. Common types include experimental, quasi-experimental, and non-experimental designs. Experimental designs involve randomly assigning participants to treatment or control groups to measure the impact of an intervention accurately. Quasi-experimental designs lack random assignment but still provide valuable insights into program effectiveness. Non-experimental designs rely on observational data and are less rigorous than experimental and quasi-experimental designs. Each design has strengths and limitations that researchers must consider when planning an impact evaluation. Choosing the most suitable design depends on various factors, including resources, time constraints, and the research question being addressed.