Which of the following are quasi-experimental designs? (1) Interrupted Time-Series Designs (2) Non-equivalent Control Group Design (3) Time Series with Non-equivalent Control (4) Block randomization

Correct option is D

Quasi-experimental designs lack full random assignment of participants to conditions. Interrupted time-series, non-equivalent control group, and time series with non-equivalent control are all classic quasi-experimental designs. Block randomization, in contrast, is a true experimental technique because it does involve random assignment (within blocks).
Information Booster:
1. Quasi-experiments are used when random assignment is impractical or unethical.
2. They sacrifice some internal validity for external/practical feasibility.
3. Non-equivalent control group designs compare pre-existing (not randomly formed) groups.
4. Time-series designs involve multiple observations before and after an intervention.