In recent years, psychology has wrestled with the broader implications of disappointing rates of replication of previously demonstrated effects. This article proposes that many aspects of this pattern of results can be understood within the classic framework of four proposed forms of validity: statistical conclusion validity, internal validity, construct validity, and external validity. The article explains the conceptual logic for how differences in each type of validity across an original study and a subsequent replication attempt can lead to replication "failure." Existing themes in the replication literature related to each type of validity are also highlighted. Furthermore, empirical evidence is considered for the role of each type of validity in non-replication. The article concludes with a discussion of broader implications of this classic validity framework for improving replication rates in psychological research.
Keywords: construct validity; external validity; internal validity; replication; research methods; statistical conclusion validity.