The Role of Meta-Analysis in Scientific Studies

Table of ContentsView AllTable of ContentsPurposeWhy It MattersReasons for UseAdvantagesDisadvantagesBiasExamples

Table of ContentsView All

View All

Table of Contents

Purpose

Why It Matters

Reasons for Use

Advantages

Disadvantages

Bias

Examples

Close

At a GlancePsychological researchers can use meta-analysis to review and analyze many studies on the same subject. While it can be a very helpful way to get a “big picture” view of a topic, meta-analysis also has limitations.

At a Glance

Psychological researchers can use meta-analysis to review and analyze many studies on the same subject. While it can be a very helpful way to get a “big picture” view of a topic, meta-analysis also has limitations.

A meta-analysis is a type of statistical analysis in which the results of multiple studies are combined and then analyzed. Researchers can perform this type of study when there have been previous studies looking at the same question.

A meta-analysis is a type of statistical analysis where researchers review, combine, and analyze the results of multiple studies (integrated results). Meta-analysis is useful when there have been many previous studies on the same topic or asking the same question.

This article discusses when meta-analysis might be used and why it’s important. It also covers some advantages and disadvantages of using meta-analysis in psychology research.

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What Is Meta-Analysis?

A simple definition of meta-analysis in psychology is that it’s a study of past studies on a subject that can give researchers a “big picture” view of the topic. To do a meta-analysis, a researcher reviews the published studies on a topic and then analyzes all the results to look for trends. Meta-analysis is used inpsychology, medicine, and other fields.

New studies from around the world are constantly being published, so the amount of research that’s out there on any given topic can be overwhelming. A meta-analysis is helpful because it’s designed to summarize all the research information on a subject. There are a few general principles that a meta-analysis follows:

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Why Is Meta-Analysis Important?

Reasons Researchers Do Meta-Analysis

In addition to summarizing and analyzing integrated results, a meta-analysis also has other uses. For example, psychology researchers can use a meta-analysis to:

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Increasing Sample Size

One of the reasons why meta-analyses are used is to overcome a very common problem in research: smallsample sizes.

Even though researchers would often prefer to have a large sample size for a study, it requires more resources, such as funds and personnel, than a small sample size does. When individual studies do not use a large number of subjects, it can be harder to draw reliable and valid conclusions from the findings.

A meta-analysis helps overcome the issue of small sample sizes because it reviews multiple studies from the same subject area, essentially creating a larger sample size.

Establishing Statistical Significance

Meta-analyses can also help establishstatistical significanceacross studies that might otherwise seem to have conflicting results. Statistical significance refers to the probability of the study’s results being due to random chance rather than an important difference.

When you consider multiple studies at the same time, the statistical significance that is established is much greater than it would be in one study on its own. This is important because statistical significance increases the validity of any observed differences in a study, which, in turn, increases the reliability of the information researchers may glean from the findings.

Benefits of a Meta-Analysis

Meta-analyses offer many advantages over individual studies. Here are just a few benefits of meta-analysis:

Meta-analysis provides a view of the research that has been done in a particular field, summarizes and integrates the different findings, and provides possible directions for future research.

Although it can be a powerful research tool, meta-analysis does have disadvantages:

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Types of Bias in Meta-Analysis

Even straying slightly from the protocol can produce biased and misleading results. The three main types of bias that can be a problem in meta-analysis are:

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Examples of Meta-Analysis in Psychology

It can be helpful to look at how a meta-analysis might be used in psychology to research specific topics. For example, imagine that a small study showed that consuming sugar before an exam was correlated to decreased test performance. Taken alone, such results would imply that students should avoid sugar consumption before taking an exam. However, a meta-analysis that pools data looking at eating behavior and subsequent test results might demonstrate that this previous study was an outlier.

Here are a few examples of meta-analysis that have been published on topics in psychology:

Summary

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9 SourcesVerywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.‌George Washington University.Study design 101: Meta-analysis.Cochrane Library.Chapter 10: Analysing data and undertaking meta-analyses.Wilson, LC. American Psychological Association.Introduction to meta-analysis: a guide for the novice.Paul J, Mojtaba Barari.Meta‐analysis and traditional systematic literature reviews—What, why, when, where, and how?Psychology & Marketing. 2022;39(6):1099-1115. doi: 10.1002/mar.21657Maziarz M.Is meta-analysis of RCTs assessing the efficacy of interventions a reliable source of evidence for therapeutic decisions?Studies in History and Philosophy of Science. 2022;91:159-167. doi: 10.1016/j.shpsa.2021.11.007Cochrane.When not to use meta-analysis in a review.Association for Psychological Science.Meta-analysis helps psychologists build knowledge.Mikolajewicz N, Komarova SV.Meta-analytic methodology for basic research: a practical guide.Front Physiol. 2019;10:203. doi:10.3389/fphys.2019.00203František Bartoš, Maier M, Shanks DR, Stanley TD, Sladekova M, Eric‐Jan Wagenmakers.Meta-analyses in psychology often overestimate evidence for and size of effects.Royal Society Open Science. 2023;10(7). doi:10.1098/rsos.230224Additional ReadingWalker E, Hernandez AV, Kattan MW.Meta-analysis: Its strengths and limitations.Cleve Clin J Med.2008;75(6):431-439. doi:10.3949/ccjm.75.6.431

9 Sources

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.‌George Washington University.Study design 101: Meta-analysis.Cochrane Library.Chapter 10: Analysing data and undertaking meta-analyses.Wilson, LC. American Psychological Association.Introduction to meta-analysis: a guide for the novice.Paul J, Mojtaba Barari.Meta‐analysis and traditional systematic literature reviews—What, why, when, where, and how?Psychology & Marketing. 2022;39(6):1099-1115. doi: 10.1002/mar.21657Maziarz M.Is meta-analysis of RCTs assessing the efficacy of interventions a reliable source of evidence for therapeutic decisions?Studies in History and Philosophy of Science. 2022;91:159-167. doi: 10.1016/j.shpsa.2021.11.007Cochrane.When not to use meta-analysis in a review.Association for Psychological Science.Meta-analysis helps psychologists build knowledge.Mikolajewicz N, Komarova SV.Meta-analytic methodology for basic research: a practical guide.Front Physiol. 2019;10:203. doi:10.3389/fphys.2019.00203František Bartoš, Maier M, Shanks DR, Stanley TD, Sladekova M, Eric‐Jan Wagenmakers.Meta-analyses in psychology often overestimate evidence for and size of effects.Royal Society Open Science. 2023;10(7). doi:10.1098/rsos.230224Additional ReadingWalker E, Hernandez AV, Kattan MW.Meta-analysis: Its strengths and limitations.Cleve Clin J Med.2008;75(6):431-439. doi:10.3949/ccjm.75.6.431

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

‌George Washington University.Study design 101: Meta-analysis.Cochrane Library.Chapter 10: Analysing data and undertaking meta-analyses.Wilson, LC. American Psychological Association.Introduction to meta-analysis: a guide for the novice.Paul J, Mojtaba Barari.Meta‐analysis and traditional systematic literature reviews—What, why, when, where, and how?Psychology & Marketing. 2022;39(6):1099-1115. doi: 10.1002/mar.21657Maziarz M.Is meta-analysis of RCTs assessing the efficacy of interventions a reliable source of evidence for therapeutic decisions?Studies in History and Philosophy of Science. 2022;91:159-167. doi: 10.1016/j.shpsa.2021.11.007Cochrane.When not to use meta-analysis in a review.Association for Psychological Science.Meta-analysis helps psychologists build knowledge.Mikolajewicz N, Komarova SV.Meta-analytic methodology for basic research: a practical guide.Front Physiol. 2019;10:203. doi:10.3389/fphys.2019.00203František Bartoš, Maier M, Shanks DR, Stanley TD, Sladekova M, Eric‐Jan Wagenmakers.Meta-analyses in psychology often overestimate evidence for and size of effects.Royal Society Open Science. 2023;10(7). doi:10.1098/rsos.230224

‌George Washington University.Study design 101: Meta-analysis.

Cochrane Library.Chapter 10: Analysing data and undertaking meta-analyses.

Wilson, LC. American Psychological Association.Introduction to meta-analysis: a guide for the novice.

Paul J, Mojtaba Barari.Meta‐analysis and traditional systematic literature reviews—What, why, when, where, and how?Psychology & Marketing. 2022;39(6):1099-1115. doi: 10.1002/mar.21657

Maziarz M.Is meta-analysis of RCTs assessing the efficacy of interventions a reliable source of evidence for therapeutic decisions?Studies in History and Philosophy of Science. 2022;91:159-167. doi: 10.1016/j.shpsa.2021.11.007

Cochrane.When not to use meta-analysis in a review.

Association for Psychological Science.Meta-analysis helps psychologists build knowledge.

Mikolajewicz N, Komarova SV.Meta-analytic methodology for basic research: a practical guide.Front Physiol. 2019;10:203. doi:10.3389/fphys.2019.00203

František Bartoš, Maier M, Shanks DR, Stanley TD, Sladekova M, Eric‐Jan Wagenmakers.Meta-analyses in psychology often overestimate evidence for and size of effects.Royal Society Open Science. 2023;10(7). doi:10.1098/rsos.230224

Walker E, Hernandez AV, Kattan MW.Meta-analysis: Its strengths and limitations.Cleve Clin J Med.2008;75(6):431-439. doi:10.3949/ccjm.75.6.431

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