Final answer:
The case study method is most likely to fail to generalize because it focuses on a single subject and does not represent a broader population.
Step-by-step explanation:
The research method that often fails to generalize is the case study. Case studies involve in-depth research regarding a single person, event, or group. This method provides detailed and rich qualitative data but has limited generalizability because it focuses on one specific subject, which may not represent the broader population. Surveys, experiments, and correlational studies are better suited to generalize findings to a larger group because they often involve larger and more random samples.