Abstract:

BACKGROUND: The comparative study of groups design data is to compare the difference of response variable measurements on two or more groups of respondents. The Meta-analysis on the studies of this kind of design information is theoretically comparative maturity and consummate, but the researchers and system evaluators still face many difficulties during the Meta-analysis of groups design data. The Meta-analysis on group comparison study requires selecting carefully different effect sizes based on the structure of response variable.
OBJECTIVE: To explore the effect size selection and announcements of response variable of different structure in Meta-analysis of groups design data.
METHODS: Articles related to Meta-analysis or systematic review methodology literature about group comparison studies for the continuous, dichotomous, and combined outcomes in CNKI database, VIP database, Wanfang Chinese Doctoral database (1990/2009), and Pubmed database (1979/2009) were retrieved by computer. Outdated and repetitive researches were excluded.
RESULTS AND CONCLUSION: Totally 30 literatures were involved for summarization according to inclusion criteria. It is relatively common that outcome variables were presented in continuous or dichotomous forms in the research literature, in some situations, it may be more applicable, but when continuous outcome variables were converted to percentage, the determination of cut points may be too arbitrary after converted to percentage analysis, and some information were lost after the treatment of continuous variable dichotomy. It is still facing a huge methodological challenge for meta-analysis. In this review, we introduced a approach based on several treatments commonly used, namely, bayesian reconstruction method, which is based on bayesian model class (Hierarchical Bayesian Models) will overcome the shortcomings of arbitrary determination of cut points and information default.