Skelton Medical Libraries Mercer University School of Medicine Mercer School of Medicine Medical Libraries Apps Help Mercer School of Medicine Medical Libraries
Introduction Requirements Steps Anatomy Online Training Quality Assessment Library Help Tools Covidence

During the course of conducting your systematic review, you should go through each of the following steps:

  1. Developing the topic and refining your PICO
    When you begin your systematic review, you will want to think about the population, interventions, comparators, and outcomes that you are interested in examining. You can then use these criteria to help develop your Key Question(s), which will serve as the overall guiding force behind your systematic review. To learn more about developing your PICO and Key Question, check out the The MUSM Skelton Medical LIbraries EBM site.
  2. Determining your study eligibility criteria
    In addition to your PICO, you will want to determine which other criteria you want each included study to have, or which criteria will make a study ineligible for your review. A few criteria to consider include study design, dates of interest, whether you will include non-English studies, study duration, and setting.
  3. Searching for studies
    In this step, you will design a comprehensive search strategy to capture the majority of the literature on your given topic. You can use your PICO as the starting point when brainstorming for terms to search. Once you have created your initial search, you will also want to decide which databases (e.g. PubMed, Web of Science, Cochrane, etc.) to search and translate your search for those databases. In addition to the published literature, you will also want to consider searching for unpublished or "grey" literature. Grey literature can be found in many sources, including manufacturers websites, the FDA website for drug information, and clinical trial registries like and the WHO International Clinical Trials Registry Platform.
  4. Creating and registering your protocol
    Your protocol should contain all of the steps outlined above and a plan for all of the steps outlined below. You can register your protocol at PROSPERO, to ensure that someone else starting a review will not be duplicating your efforts.
  5. Screening and selecting studies
    This step includes both a preliminary review of all titles/abstracts to determine which studies are potentially eligible, and an additional, more in-depth review of the full text for all includes from the title/abstract phase to determine final eligibility for the review. This step will require two people to review each abstract and each full-text document, plus an additional reviewer to serve as a tie breaker.
  6. Data extraction
    You can use your PICO as a guide for the data you want to extract, including information on the study population, intervention or exposure, comparator (if applicable), outcomes data, timing of data, and study design. There are a number of tools that you can use for this step, ranging from a basic Excel setup to more sophisticated tools designed for systematic review data abstraction, like AHRQs Systematic Review Data Repository (SRDR) and Covidence. To complete this step, you will need at least one team member to go through and extract all relevant data from each included study and one team member to review the data they have extracted. 
  7. Quality assessment
    In this step, you will assess the internal validity of each study, including systematic errors (e.g. selection bias, confounding), nonsystematic errors (errors attributable to chance), and inferential errors (problems in data analysis and interpretation). Depending on the types of studies you are examining, you may want to select a pre-existing quality rating tool for each study type. A sample of quality rating tools can be found in the box to the right.
  8. Assessment of applicability
    In this step, you will assess the external validity of each study (how well the results of the study are likely to reflect real-world outcomes), as well as the external validity of the body of literatures as a whole. You can also use your PICO to determine the most important factors affecting applicability. Some issues to consider here are how narrow the exclusion criteria were within each study, differences between patients in the study and in the community, whether or not a medication regimen is reflective of current practice, and whether an interventions intensity would be feasible for routine use.
  9. Presentation of findings
    In this step, you will develop your evidence tables, which give detailed information for each study (using your PICO as a guide), and summary tables, which give a high level overview of the findings of your review. You can create evidence and summary tables to describe study characteristics, results, or both. These tables will help you determine which studies, if any, are eligible for quantitative synthesis.
  10. Quantitative synthesis
    Quantitative synthesis, also known as meta-analysis or pooling, is the process of combining data from multiple studies in order to gain a sense of the overall effect of a treatment or exposure. When determining whether or not a meta-analysis should be undertaken, great care should be taken to determine whether or not the studies are similar enough to analyze together, and whether or not an analysis will provide potentially misleading results. There are a number of tools that can be used to conduct a meta-analysis, including RevMan, CMA, and Stata.
  11. Grading the strength of evidence
    Strength of evidence grades are used to evaluate the strength of the entire body of evidence for major outcomes and comparisons. Strength of evidence is a single grade based on four domains: risk of bias, consistency, directness, and precision. For more information on grading strength of evidence, check out the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group.
  12. Writing your review
    Your final review manuscript should contain the following sections: title, abstract, introduction, methods, results, discussion, and disclosure of funding. In addition to these main sections, you should also consider including appendices with your complete evidence tables and quality assessment forms and a line-by-line description of your search methodology.

For additional, step-by-step guidance, check out the AHRQ Training Modules

Contact Us

33 West 11th Street, Columbus, GA 31902

501 Mercer University Drive, Macon, GA 31207

1250 East 66th Street, Savannah, GA 31404

Quick Links

Staff Directory

Resources A to Z


Renew Books/Models

InterLibrary Loan
4-H Facebook NLM GALILEO
© 2021 Mercer University School of Medicine. All rights reserved.