Replication studies in second language acquisition research: <i>Definitions, issues, resources, and future directions</i>

Abstract A long-standing concern in the field of second language acquisition is that replication studies are not only infrequent but also poorly designed, reported, and labeled. This special issue responds to an urgent need for action by showcasing eleven high-quality replication studies. In doing so, this collection highlights exemplary standards in replication study design and reporting. This introduction to the special issue provides readers with a point of reference for what replication research is, including why replication studies are needed, issues about originality and innovation in replication research, how replication studies can be designed and conducted, and recent advances and resources to support future replication efforts in the field. The introduction concludes with an overview of each study in the special issue, highlighting its main components and discussing how the replication strengthens the field and advances knowledge and understanding about the topic.