How do quasi-experiments differ from experiments in political science research?

• A. Quasi-experiments are observations in the real world without random assignment
• B. Quasi-experiments have complete control over participants and conditions
• C. Quasi-experiments manipulate variables in a lab
• D. Quasi-experiments are purely theoretical

Answer: (A)

Quasi-experiments differ from experiments in political science research mainly in assignment of the treatment. In a true experiment, researchers randomly assign units to receive the treatment or to serve as controls and actively manipulate the independent variable in a controlled setting. In a quasi-experiment there is no random assignment; researchers study real-world settings where policy changes or events affect some units but not others, and then use design techniques (like natural experiments, difference-in-differences, or regression discontinuity) to approximate causal inference from observational data. This approach acknowledges and tries to account for confounding factors that could otherwise bias the comparison. The other descriptions describe scenarios with full manual control, lab manipulation, or purely theoretical work, which do not capture the essence of quasi-experimental research.