Meta Analysis

A meta-analysis is similar to a smoothie in that you combine many ingredients, and you get a single drink at the end. A meta-analysis is a quantitative technique that combines the results of multiple studies and ends with a summative figure/ estimate. A meta-analysis essentially is a summary, in effect, of numerous studies to form one finding that covers the area of study.

The purpose of meta-analyses is to identify if the collaborative study’s findings support or disprove a hypothesis proposed by the research overall.

• We will start by looking at the meta-analysis meaning and how a meta-analysis in research is used.
• Moving on to cover the meta-analysis methodology frequently used by researchers.
• Then we will take a look at an actual meta-analysis example.
• Afterwards, we will explore meta-analysis vs systematic review to identify the stark differences between the two research methods.
• Finally, we will look at the advantages and disadvantages of using meta-analysis in psychology research.

Figure 1: Research. Credit: flaticon.com/Freepik

The Meta-Analysis Meaning

What do we mean by a meta-analysis?

A meta-analysis is a research technique researchers frequently use in psychology to summarise key findings of multiple studies. The research method collects quantitative, meaning numerical data.

Meta-Analysis in Research

Researchers use a meta-analysis to understand psychology research’s general direction in a specific area.

The research method is also commonly used to identify whether current research supports and establishes existing interventions as effective or ineffective. Or to find a more precise, generalisable conclusion. As meta-analyses utilise multiple studies to form a conclusion, the findings are more likely to be statistically significant as a larger data pool is used.

Meta-Analysis Methodology

When deciding to perform a meta-analysis of existing research, a researcher will typically involve in the following steps:

• Researchers identify the area of interest for the research and formulate a hypothesis.
• Researchers create inclusion/exclusion criteria. For example, in a meta-analysis looking into the effects of exercise on mood, exclusion criteria may include studies using participants that are using medication that affects affective states.

• Researchers will use a database to identify all of the research similar to what the hypothesis is investigating. Several established databases in psychology include published work. In this stage, researchers need to search key terms that summarise what the meta-analysis is investigating to identify studies that also investigated similar factors/ hypotheses.
• Researchers will determine which studies will be used based on the inclusion/exclusion criteria. From the studies found in the database, the researcher must decide whether they will be used.
  • Studies included meeting the criteria of the inclusion criterion.
  • Studies excluded meeting the criteria of the exclusion criterion.
• Researchers appraise the research studies. Appraising studies is a crucial stage in the meta-analysis methodology that checks the reliability and validity of included studies. Studies low in reliability or validity are usually not included in the meta-analysis.

Meta-Analysis vs Systematic Review

Meta-analysis and systematic review are standard research techniques used in psychology. Although similar research processes, stark differences between the two exist.

A systematic review is one of the stages of the meta-analysis methodology. During a systematic review, the researcher uses a precise method to collect relevant studies from scientific databases relevant to the research area. Like a meta-analysis, the researcher creates and uses inclusion/ exclusion criteria. Rather than giving a quantitative summative figure, it identifies and summarises all the relevant research concerning the research question.