How are response ratios used in meta-analysis?
The response ratio (the ratio of mean outcome in the experimental group to that in the control group) and closely related measures of proportionate change are often used as measures of effect magnitude in ecology. Using these metrics for meta-analysis requires knowledge of their statistical properties, but these have not been previously derived.
How are generalized linear mixed models used in meta-analysis?
General formulation of generalized linear mixed models for meta-analysis of binary outcomes. The generalized linear mixed effects model (GLMM) extends the generalized linear model by including random effects in addition to fixed effects (hence mixed-effects model).
Why are GLMMs used in meta-analysis of binary outcomes?
GLMMs are believed to overcome the problems of the standard random-effects model because they use a correct binomial-normal likelihood. However, this belief is based on theoretical considerations, and no sufficient simulations have assessed the performance of GLMMs in meta-analysis.
How is the treatment effect determined in a meta-analysis?
In a meta-analysis, the study effects correspond to the intercept, and the treatment effect to the slope of treatment/control indicator in the logistic regression; the log odds ratio (LOR) is the difference between the log odds of the treatment and control groups.
Using these metrics for meta-analysis requires knowledge of their statistical properties, but these have not been previously derived. The authors give the approximate sampling distribution of the log response ratio, discuss why it is a particularly useful metric for many applications in ecology, and demonstrate how to use it in meta-analysis.
How is a fixed effect meta-analysis calculated?
A fixed-effect meta-analysis using the inverse-variance method calculates a weighted average as: where Yi is the intervention effect estimated in the ith study, SE i is the standard error of that estimate, and the summation is across all studies.
Why are some studies excluded from a meta-analysis?
The standard practice in meta-analysis of odds ratios and risk ratios is to exclude studies from the meta-analysis where there are no events in both arms. This is because such studies do not provide any indication of either the direction or magnitude of the relative treatment effect.
Do you do a meta-analysis in a systematic review?
Do not do a meta-analysis. A systematic review need not contain any meta-analyses. If there is considerable variation in results, and particularly if there is inconsistency in the direction of effect, it may be misleading to quote an average value for the intervention effect.