Contents
What does weight mean in a meta-analysis?
Most meta-analysts use weights of one sort or another when calculating the overall mean and variance of effect sizes. Unit weights ignore the possibility that different studies provide different amounts of information (precision). Unit weights are thus generally considered inferior.
Why are studies weighted in meta-analysis?
The usual statistical method for combining results of multiple studies is to weight studies by the amount of information they contribute (more specifically, by the inverse variances of their effect estimates). This gives studies with more precise results (narrower confidence intervals) more weight.
What is the purpose of meta-analysis?
Meta-analyses are conducted to assess the strength of evidence present on a disease and treatment. One aim is to determine whether an effect exists; another aim is to determine whether the effect is positive or negative and, ideally, to obtain a single summary estimate of the effect.
How is a weighted average produced in a meta-analysis?
Existing methods for meta-analysis yield a weighted average from the results of the individual studies, and what differs is the manner in which these weights are allocated and also the manner in which the uncertainty is computed around the point estimate thus generated.
What is the purpose of a meta-analysis?
Purpose: A meta-analysis of aggregate data (AD) uses statistical analyses to generate a summary (pooled) estimate using effect estimates of individual studies reported in the published literature.
How long does it take to do an IPD meta-analysis?
IPD meta-analyses take more time to complete (several years), cost significantly more (to cover cost of personnel, data housing, data cleaning and harmonization), and can face more challenges in obtaining the data (original study investigators must agree to share original data) than meta-analyses of AD (Cooper and Patall, 2009; Riley et al. 2010).
How to conduct a meta-analysis of aggregate data?
Steps of a Meta-Analysis of Aggregate Data: 1. Conduct a systematic review of the literature: The first step in conducting a meta-analysis of AD is to conduct a systematic review. A systematic review is primarily focused on identifying all of the available, relevant studies that are related to a specific and well-defined question of interest.