 In summary, for Schmidt, direct replications control for sampling error, artifacts, and fraud, and provide information about the reliability and validity of prior empirical work. Conceptual replications help corroborate the underlying theory or substantive (as opposed to statistical) hypothesis in question and the extent to which they generalize in new circumstances and situations. In practice, direct and conceptual replications lie on a continuum, with replication studies varying more or less compared to the original on potentially a great number of dimensions.