Systematic reviews attempt to gather all relevant studies that address the same research question. Developing a specific research question along with inclusion and exclusion criteria is essential. Doing so will help identify key concepts that will be used in a search strategy.
A research question should be open-ended, comprehensive and specific. It can include elements found in different frameworks and tools. PICO is a frequently used approach when devising research questions in the fields of health and medicine.
The following examples of research questions are then mapped out using PICO.
|Example 1||Example 2|
|Population or Problem||hospital acquired infections||high school students|
|Intervention||hand washing||sexual education programs|
|Comparison||no hand washing, gloves, hand sanitizers||no program, abstinence programs|
|Outcome||reduced infection||increased knowledge, attitude changes, rates of sexual activity, rates of teen pregnancy|
In addition to a specific research question, a systematic review requires a list of inclusion and exclusion criteria. This list will be used when screening results. Criteria could include populations, types of publication, language, years, types of study, sample size and more.
Feel free to use a search strategy worksheet to start preparing your review. This worksheet helps identify the research question, relevant concepts along with useful synonyms.
Searching for previously published systematic reviews serves two purposes. First, it verifies that a current and comprehensive review that addresses the same question has not been published recently. Second, it identifies search strategies that have been used previously. These strategies can provide useful information such as keywords, subject headings, operators, limits, databases and other resources that could be reused if appropriate.
If a published review focuses on only one of the key concepts of your research question, you can nevertheless draw on its strategies to assist in developing your own.
Resources for finding systematic reviews
Systematic reviews are often conducted by review teams that include:
Consideration should be given to establishing a team prior to conducting the review.
A systematic review protocol describes the rationale for the review and its objectives along with the research question it seeks to address. It also describes the methodology, including the search strategy, that will be used to locate, select and critically appraise studies. Finally, it explains how data from the included studies will be collected and analyzed.
Writing a protocol keeps the review on track and helps reflect on any underlying assumptions about the topic while justifying and defending various decisions that were made.
The Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols, or PRISMA-P, was developed "to facilitate the development and reporting of systematic review protocols" in health and medicine. It includes a detailed, 17-point checklist that can be used when writing a protocol. Researchers producing health-related reviews can register their protocols using PROSPERO.
Biology and environmental studies have standards called RepOrting standards for Systematic Evidence Syntheses (ROSES), which include forms for protocols and systematic reviews.
Here are a few examples of registered or published protocols:
Various templates are available and can be used to help prepare a protocol: