Interpreting Students' Interpretations of Research

This article examines the role of random sampling and random assignment in the interpretation of research results. Students and faculty were asked two multiple-choice questions about research methods. When questioned about the role of random sampling, 75% of all subjects correctly associated it with generality inference (generalizability). When asked about the role of random assignment, however, only 27% of all subjects correctly associated it with causal inference. The remaining subjects allocated at least some part of the role of random assignment to generalizability. We suggest that these findings reflect a bias in psychologists' training due to teaching a statistical model that stresses random sampling and generality inference. We discuss the random assignment model, which focuses on causal inference, and recommend that both models be taught in introductory methods and statistics courses.