In this article, we review empirical studies that research critical reflection based on Mezirow's definition.The concepts of content, process, and premise reflection have often been cited, and operationalizing Mezirow's high-level transformative learning theory and its components has been the endeavor of adult education and human resource development(HRD) researchers.By conducting a literature review, we distill 12 research studies on critical reflection that we dissect,analyze,and compare.Discovering different approaches,assessment processes,and outcomes leads us to the conclusion that there is little agreement on how to operationalize reflection. We suggest four improvements:(a) integrating different critical reflection traditions, (b) using multiple data collection pathways,(c) opting for thematic embedding,and(d) attending to feelings.By implementing these improvements,we hope to stimulate closer alignment of approaches in critical reflection research across adult education and HRD researchers