Abstract
This article reports the results of a study investigating how undergraduates evaluate realistic scientific data in the domains of geology and paleontology. The results are used to test several predictions of a theory of data evaluation, which we call models-of-data theory. Models-of-data theory assumes that when evaluating data, the individual constructs a particular kind of cognitive model that integrates many features of the data with a theoretical interpretation of the data. The individual evaluates the model by attempting to generate alternative causal explanations for the events in the model. We contrast models-of-data theory with other proposals for how data are cognitively represented and show that models-of-data theory gives a good account of the pattern of written evaluations of data produced by the undergraduates in the study. We discuss theoretical and instructional implications of the theory.