Purpose: Researchers commonly utilize coding-based analysis of classroom asynchronous discussion contributions as part of studies of online learning and instruction. However, this analysis is inconsistent from study to study with over 50 coding schemes and procedures applied in the last eight years. The aim of this article is to provide a basis for more consistent use of coding schemes and to facilitate comparison of studies utilizing different coding schemes. Design/methodology/approach: The paper identifies coding schemes presented in the research literature, classifies these schemes, and presents a list of synthesis codes reflecting the content of the many different schemes for each classification. Findings: Based on the initial and follow-up literature review, 56 different coding schemes were identified as having been employed within the last eight years. Initial sorting indicated that schemes primarily focused on identifying critical thinking, describing social interactions, or characterizing online discussion. Originality/value: In addition to offering a comprehensive resource reflecting the coding schemes currently applied to the analysis of online, asynchronous discussion, the meta-analysis results also inform regarding the current state of research in this area. In addition, current research trends and areas for potential new research and development are revealed. (Contains 22 tables.)