This work focused on issues related to data collection in meta-analysis, specifically the coding process by which coders extract data from primary studies. This work used content analysis to evaluate 118 meta-analyses reported in 99 journal articles from the educational literature to establish how educational researchers assess and report intercoder reliability. The principal investigator provides detailed information regarding the assessment of intercoder reliability using an item-by-item approach and a generalizability theory framework for the instrument used in the study. The principal investigator explored six topics related to the assessment and reporting of intercoder reliability: the use of meta-analysis in education, coders and coding strategy, coder training procedures, the code book, addressing intercoder reliability, and reporting intercoder reliability. Although the literature review established that researchers perceive coder unreliability as a threat to the internal validity of a study, of the 118 meta-analyses in the study, authors reported intercoder reliability analyses less than half (37.3%) of the time. The principal investigator presents recommendations for best practice in intercoder reliability analysis and reporting based on the study methodology and research findings.