Effect sizes and research directions of peer assessments: From an integrated perspective of meta-analysis and co-citation network

Peer assessments (PA) have been widely explored by researchers over the past few decades. However, their impact on various learning environments remains unclear. Based on a meta-analysis, this study aimed to analyze PA-based research performed across multiple learning environments. Unlike existing meta-analyses, however, this study integrated co-citation network analysis with the meta-analysis to examine the bibliometric relationships between the analyzed studies. This method provides citation-based evidence to secure the association of research data for conducting the meta-analysis. In addition, the visualized research network offers a fresh micro-to-macro understanding of the PA literature. A total of 20 PA-related core articles consisting of their follow-up 340 citing studies were collected based on systematic keyword searches. All analyzed articles were published between 1998 and 2020, and were sourced from two renowned databases, the Web of Science and Scopus, in order to maintain the quality of the data used for this present research. The main findings are twofold. First, the meta-analysis reported that the standard error at the 95% confidence interval for the average difference between the experimental and control groups is [0.288, 0.424], indicating that each effect value in the meta-analysis is heterogeneous. We also found that technology combined with PA teaching methods has certain learning effects in the contexts of web-based problem-solving activities. In addition, following Fu and Hwang's (2018) constructivist theoretical framework, we propose some criteria for conducting peer assessment research. Second, the co-citation network analysis presented a visualized networking structure of 20 PA articles, of which 11 were bibliographically connected. This result echoed the previous research by reviewing the relationships between the studies in the meta-analysis. Moreover, the co-citation network of PA research reveals some heavy co-citation links from the 11 core articles. The results further identified the main research foci include combining PA with technology-enhanced learning environments (e.g., game- and web-based learning) and PA activities for collaborative learning in the field. In conclusion, this study presents an innovative approach to examining the effects of empirical PA studies and, accordingly, offers discussions and directions for future research.