Abstract:

BACKGROUND: In most Meta-analysis of two-group comparison study, the outcome variables of original research literature are quite different between different researches, so outcome variables cannot be directly compared, limiting Meta-analysis.
OBJECTIVE: To investigate methods for mining the information of original research and enhance the performance of Meta-analysis.
METHODS: According to the outcome variables of the original research, 10 common standardized mean difference effect size calculation methods were described.
RESULTS AND CONCLUSION: Before conducting Meta-analysis of two-group comparison study, we should consider all kinds of possible situations, especially when there were some distances between the original research literature information and those we have grasped. We have to dig information as much as possible to avoid information loss.