In modern research, with the increase of data, how to effectively integrate and analyze the results from multiple studies has become a challenge faced by many scholars. Meta-regression analysis came into being. This method is favored by researchers because it can not only compare and synthesize the results of multiple studies, but also adjust the impact of variables, thereby providing more accurate data support for policymakers.
Meta-regression analysis aims to reconcile conflicting research results or to strengthen consistent findings.
The basic principle of meta-regression analysis is to combine data sets from different studies, either individual data from a single study or aggregated data. Aggregate data usually include summary statistics such as sample mean and effect size, while case data provide more original observations, making the information more flexible. While aggregate data are relatively simple and inexpensive to compile, access to individual case data is often hampered by privacy and confidentiality issues and is often limited to internal use by the research implementation team.
Meta-regression is a statistically rigorous method in systematic reviews that allows for efficient analysis of the effects of variables.
For the statistical analysis of research results, the choice of meta-regression model is crucial. Depending on the type and characteristics of the data used, researchers can choose different models. For example, the fixed effects model is suitable when there is no significant difference between studies, while the random effects model can reflect the heterogeneity between studies. This heterogeneity includes not only sampling errors but also other influencing variables, which makes the research results more reliable.
The random effects meta-regression model can reflect the variability of treatment effects, which to some extent also takes into account the diversity of samples.
When conducting meta-regression analysis, researchers are often faced with a choice between two models: a fixed effects model and a random effects model. The fixed effects model was used under the assumption that the studies lacked substantial differences, and its model equation can be simplified to ytk = xtk′β + ɛtk. In the random effects model, researchers need to take into account the variability between different studies, which is why many fields choose to use the random effects model today.
Meta-regression can enhance the reproducibility of research and the ability of sensitivity analysis when considering the influence of variables.
Meta-regression analysis has a wide range of applications, including economics, business, energy and water policy. Through quantitative review, researchers can study and analyze the changes in prices and income elasticity of different commodities and make reasonable assessments of the productivity spillover effects of multinational corporations. In terms of environmental policies, meta-regression analysis can also provide some valuable insights into water resources management and environmental protection.
The use of meta-regression can help to conduct cost-effectiveness analysis of policies or programs across multiple studies.
As meta-regression analysis has become increasingly popular, researchers have expressed varying opinions on its utility and limitations. Despite the various tests of heterogeneity assumptions, when choosing a meta-regression model, some researchers recommend choosing random effects meta-regression anyway because it better captures the variability between studies.
Ultimately, meta-regression analysis not only facilitates the transfer of knowledge between different fields, but also provides researchers with a flexible and practical tool to help them unravel more complex puzzles of research results. However, faced with such rich and complex data analysis, how should researchers find the best balance between selecting methods and interpreting results?