Overreliance on one measurement approach can challenge accurate statements about reality, as findings can represent by-products of the compulsory measurement paradigm. Within the theory of planned behavior (TPB), the compatibility principle represents one such strictly imposed paradigm. Using 2 cross-sectional surveys of 1,394 volunteers and involving structural equation models, we demonstrate that the widely employed practice of measuring TPB constructs is confounded with method-implied bias. This means the theory cannot conclusively reveal origins of a behavior. Our results also suggest that on an aggregated level, when method bias is eliminated, its constructs are linked in hypothesized ways. Adopting a more general model—thus, adopting a more traitlike conceptualization of attitudes—has interesting implications for social psychology and its current trends.