Systematic Reviews and Meta-Analysis — Open & Free

Systematic Reviews and Meta-Analysis: A Campbell Collaboration Online Course provides an overview of the steps involved in conducting a systematic (scientific) review of results of multiple quantitative studies. These steps include: problem formulation, searching for relevant literature, screening potentially eligible studies, coding and critically appraising studies, synthesizing results across studies using meta-analysis, reporting and disseminating results, and updating or re-analysis of data.


February 2023 Update:

Systematic Reviews and Meta-Analysis is a brand new online course from The Campbell Collaboration and the Open Learning Initiative.

We proudly invite you to use the material for free during this pilot phase, with one condition — that you agree to help us make it even better! Since you’re among the first people to use this course, your insights will be invaluable as we seek to create clearer instruction, more meaningful examples, and helpful assessments.

In the near future, we will reach out via email to independent learners who used these materials to build new skills, and to the instructors who shared the course with their students. Your survey results will help us to continuously improve the content and boost its effectiveness. Campbell and OLI will also host a live webinar where you can interact directly with us to ask your questions and share your feedback. Watch your email for that announcement.


When used together, systematic review methods and meta-analysis can produce comprehensive, accurate, and useful summaries of empirical evidence to answer questions that are relevant for policy, practice, and future research. Systematic reviews and meta-analysis can also uncover previously-undetected patterns of results across multiple studies, leading to new discoveries. For these reasons, systematic reviews and meta-analysis have become popular tools that are widely used – and misused – in the social, health, and natural sciences. A growing body of meta research has been used to develop evidence-based guidelines for the conduct and reporting of rigorous systematic reviews and meta-analysis. The Campbell Collaboration developed such guidelines for reviews in the social, behavioral, and economic sciences, and these guidelines undergird the content of this course.

A systematic approach is necessary to identify relevant studies and avoid well-documented sources of bias and error in the dissemination, assessment, and synthesis of research results across studies. Meta-analysis provides a set of statistical tools for analysis and synthesis of quantitative data from two or more studies.

The course provides an introduction to the methods of systematic reviews and meta-analysis. It is appropriate for graduate students, post-doctoral fellows, faculty, and senior researchers in institutions of higher education. It is geared for participants who have already completed introductory graduate level training in research methodology and statistics. 

Access to the Open & Free version of the course is free of charge. It contains no scored assessment, has no schedule, and no instructor. Use it at your own pace. The content of this course may not be modified or adapted for other uses.

Open & Free features

Open & Free Courses

  • Open & Free OLI courses enable independent learners to study a subject on their own terms, at their leisure. Courses are:

    • Self-guided.
    • Self-paced.
    • Self-supported.
  • Open & Free courses include only the learning materials:

    • No teacher.
    • No tests.
    • No college credit.
    • No certificate of completion.
  • *If your teacher gave you a Course Key, do not use an Open & Free course because your teacher will never see your work.

What students will learn

The course provides a general overview of all aspects of a scientific literature review, including formulating a problem, finding the relevant literature, coding studies, and meta-analysis. It follows guidelines and standards developed by the Campbell Collaboration, based on empirical evidence about how to produce the most comprehensive and accurate reviews of research. It will help students prepare systematic reviews that include meta-analysis.

Learning objectives by module

Module 1

Describe strengths and limitations of systematic reviews.

Describe systematic review methods.

Identify different types of systematic reviews.

Identify key components of a systematic review.

Module 2

Describe primary methods of meta-analysis.

Describe purposes of meta-analysis.

Describe strengths and limitations of meta-analysis.

Identify key components of meta-analysis.

Module 3

Describe roles of advisory board members.

Describe the amount of time, level of effort, and resources needed to conduct a systematic review and meta-analysis.

Explain why systematic reviews require teams.

Identify factors that contribute to the amount of time, level of effort, and resources needed.

Identify guidelines for the conduct and reporting of systematic reviews and meta-analysis.

Identify the knowledge and skills required to conduct a systematic review and meta-analysis.

Module 4

Describe tasks involved in formulating a problem for a systematic review.

Explain the importance of careful problem formulation in systematic reviews.

Identify characteristics of well-formulated questions for systematic reviews.

Identify different types of questions that can be addressed in systematic reviews.

Identify potential motivations and sources of questions for systematic reviews.

Identify questions that are not appropriate for systematic reviews.

Module 5

Describe purposes of narrow versus broad reviews.

Describe relative advantages and disadvantages of narrow versus broad reviews.

Recognize the importance of issues of scope in planning for systematic reviews.

Recognize the importance of key constructs in systematic reviews.

Module 6

Construct a logic model for a systematic review.

Construct a theory of change for a systematic review.

Describe the uses of logic models and theories of change in systematic reviews.

Module 7

Define the components of PICOS eligibility criteria.

Describe uses of eligibility criteria in systematic reviews.

Develop a well-formulated question and specify relevant inclusion and exclusion criteria.

Identify other potential eligibility criteria.

Module 8

Describe the contents of a protocol.

Describe the purposes of protocols for systematic reviews.

Describe the rationale for public registration of protocols.

Module 9

Explain how to work with an information specialist on a systematic review.

Module 10

Generate a list of scholarly databases to search that aims to achieve thorough coverage for your systematic review research question(s).

Module 11

Compare and contrast systematic review searching with traditional literature review searching.

Construct an effective concept-blocked search strategy correctly using various search elements such as subject headings, keywords and operators.

Explain how and when to use search filters, limits and hedges in a systematic review search.

Use database syntax and field searching appropriately in the design of a systematic review search strategy.

Module 12

Translate the different elements of a search from one database to another using the correct database syntax.

Module 13

Design and document a search process for grey literature sources for a systematic review.

Module 14

Use a variety of supplementary searching methods to identify additional studies related to your systematic review not found through database and grey literature searching.

Module 15

Document and report your search methods for reproducibility and transparency.

Run searches making use of database features for saving and exporting search results.

Use a citation manager to import search results and deduplicate across different sources.

Module 16

Describe the goal of the screening process.

Describe the screening process.

Module 17

Identify best practices for screening questions.

Module 18

Describe the process for training screeners.

Module 19

Describe how multiple reports on the same sample can benefit a systematic review.

Describe the screening process.

Module 20

Demonstrate understanding of percentage agreement and kappa

Identify the information that will need to be reported about the screening process.

Module 21

Describe the screening process.

Module 22

Describe purposes of data extraction and coding.

Describe steps in the process of data extraction and coding.

Module 23

Describe the rationale for linking studies and reports.

Describe the types of bibliographic information that should be extracted from included studies.

Identify intervention characteristics for data extraction (if applicable).

Identify sample characteristics that can be extracted from included studies.

Identify the types of data that need to be extracted in order to describe the methods of included studies.

Identify types of data to extract on study results.

Module 24

Describe essential principles of data extraction and coding in systematic reviews.

Describe the process for pilot testing data extraction forms.

Describe the process for training coders.

Describe the purpose and methods of reliability checks on data extraction and coding.

Describe the purposes of pilot testing.

Describe the purposes of training for coders.

Describe the rationale for using structured data extraction forms.

Describe three ways to structure data extraction forms.

Module 25

Describe diverse approaches to critical appraisal in systematic reviews.

Describe the purposes of critical appraisal in systematic reviews.

Identify key features of critical appraisal in systematic reviews.

Identify potential topics for critical appraisal.

Identify steps in selecting, adapting, and testing critical appraisal methods.

Module 26

Articulate common sources of dependent effect sizes in meta-analysis.

Describe the contents and uses of a flat file.

Identify steps for handling missing data in the extraction and coding process.

Module 27

Identify information that should be reported to describe included studies.

Identify information that should be reported to describe the coding process.

Identify two ways to report results of critical appraisal.

Module 28

Assess differences in systematic review software to choose the best option for your systematic review team.

Module 29

Articulate what standardized effect sizes are

Define effect size.

Demonstrate understanding of what probability values mean

Module 30

Demonstrate understanding of the correlation family of effect sizes

Demonstrate understanding of the mean difference family of effect sizes

Demonstrate understanding of the odds ratio family of effect sizes

Demonstrate understanding of the role of effect size variance and standard error in meta-analysis.

Module 31

Demonstrate understanding of how to read a forest plot.

Demonstrate understanding of what vote counting is

Module 32

Demonstrate understanding of how a simple meta-analysis is conducted

Demonstrate understanding of how effect size confidence intervals, precision, and weights are related

Demonstrate understanding of the general concept behind weighting

Module 33

Demonstrate an understanding of effect size heterogeneity

Demonstrate understanding of how to compute the homogeneity test

Module 34

Demonstrate an understanding of metrics used to describe heterogeneity

Demonstrate understanding of the considerations for choosing the meta-analytic model.

Describe how model choice affects the statistics arising from a meta-analysis

Module 35

Articulate benefits and challenges of using meta-regression to explore heterogeneity.

Demonstrate an understanding of challenges to interpreting moderator analyses.

Demonstrate understanding that exploring effect size heterogeneity requires careful planning in early stages of the systematic review.

Module 36

Demonstrate understanding of publication bias

Demonstrate understanding of the elements of a funnel plot

Module 37

Demonstrate understanding of iterative steps in the systematic review process.

Describe different products of systematic reviews for different audiences.

Describe the importance of logical consistency throughout a review.

Identify guidelines for the conduct and reporting of systematic reviews and meta-analysis.

Identify key components of a systematic review.

Identify key components of meta-analysis.

Identify reasons for updating and/or re-analysis of data in systematic reviews.

Module 38

Access resources for learning more about different review methods.

Describe some common review methods beyond systematic reviews.

Identify advanced meta-analytic methods.

Module 39

Access information about tools and platforms that can facilitate systematic reviews through automation.

Access resources for learning more about living systematic reviews.

Describe living systematic reviews.

Describe some steps of evidence synthesis in which automation may be applied.

Describe uses of data repositories.

Explain the role of automation in the evidence synthesis process.

Module 40

Describe the importance of systematic reviews and meta-analysis

Identify resources for learning about advancements in methods for systematic reviews and meta-analysis.

Course outline

UNIT 1: Introduction

Module 1: Systematic reviews
Module 2: Meta-analysis
Module 3: What to expect

UNIT 2: Problem formulation

Module 4: Posing answerable questions
Module 5: Setting the scope
Module 6: Using logic models and theories of change
Module 7: PICOS inclusion and exclusion criteria
Module 8: Developing a protocol

UNIT 3: Searching the Literature

Module 9: Working with an information specialist
Module 10: Identifying sources to search
Module 11: Designing Database Searches
Module 12: Translating searches across databases
Module 13: Searching the grey literature
Module 14: Supplementary searching
Module 15: Running, documenting and reporting searches

UNIT 4: Screening Potentially Eligible Studies

Module 16: Introduction to screening potentially eligible studies
Module 17: Creating a screening guide
Module 18: Training screeners and pilot testing the screening process
Module 19: Full-text screening
Module 20: Reporting standards for the screening process
Module 21: Screening potentially eligible studies unit summary

UNIT 5: Data Extraction and Coding

Module 22: Introduction to data extraction and coding
Module 23: Types of data to extract and code
Module 24: Methods of data extraction and coding
Module 25: Structured critical appraisal
Module 26: Preparing data for analysis and synthesis
Module 27: Reporting the coding process and results
Module 28: Software support

UNIT 6: Introduction to Effect Sizes

Module 29: General introduction to effect sizes
Module 30: Three families of effect sizes

UNIT 7: Introduction to Meta-Analysis

Module 31: Introduction to meta-analysis
Module 32: Meta-analysis
Module 33: Homogeneity part 1
Module 34: Homogeneity part 2
Module 35: Exploring heterogeneity
Module 36: Introduction to publication bias

UNIT 8: Course Wrap-up

Module 37: Summary of systematic review and meta-analytic methods
Module 38: Other evidence synthesis methods
Module 39: Technological advances to improve efficiency
Module 40: Conclusions

Other course details

February 2023

  1. Valentine, J. C., Littell, J. H., & Young, S. (Eds.). Systematic reviews and meta-analysis: A Campbell Collaboration online course. Open Learning Initiative, 2022. Available from https://oli.cmu.edu/courses/systematic-reviews-and-meta-analysis/
  2. See course Units for information on contributions of other authors: Pigott, T. D., Premji, Z., and Engelbert, M.

System requirements

OLI system requirements, regardless of course:

  • internet access
  • an operating system that supports the latest browser update
  • the latest browser update (Chrome recommended; Firefox, Safari supported; Edge and Internet Explorer are supported but not recommended)
  • pop-ups enabled
  • cookies enabled

Some courses include exercises with exceptions to these requirements, such as technology that cannot be used on mobile devices.

This course’s system requirements:

  • To do the activities, you will need your own copy of Microsoft Excel, Minitab, the open source R software (free), TI calculator, or StatCrunch. Probability & Statistics includes data files and software instructions, but not the statistical analysis software itself.
OLI Website:
New look and
New student registration process

OLI’s website has undergone a refresh, and so has the student registration process. Watch the video to see how easily students can register with a Course Key.

Go to Top