How we review the evidence for public health guidelines or advice

  1. DEFINING THE QUESTION
    • Start by forming an answerable question that considers the issue, the relevant population and the health outcomes of interest. This is often articulated in a PI/ECO* framework.
    • Consult on these questions to ensure they are clearly defined and reflect the most important outcomes.
  2. PLANNING THE EVIDENCE SEARCH, ANALYSIS AND REPORTING
    • Develop the search strategy (also known as the protocol). The search strategy is the process the researchers follow to look for, assess and report on the evidence. This will include research questions, PICO framework, search resources (databases), search terms (keywords), inclusion/exclusion criteria, risk of bias assessment tools, data extraction and analysis plan, timeline and investigators’ roles.
  3. SEARCHING FOR EVIDENCE
    • Contracted expert evidence reviewers search for, select and assess the relevant evidence.
    • Search databases using pre-defined search terms.
    • Perform complementary searching such as hand-searching or review of the grey literature.
    • Record the date that the searching was completed and the results retrieved.
  4. SELECTING EVIDENCE
    • Identify and remove duplicate articles, using the PRISMA framework.
    • Screen titles and abstracts against pre-defined inclusion/exclusion criteria.**
    • Screen the full text of articles using pre-defined inclusion/exclusion criteria.**
    • Using an agreed format, present results of the screening process.
  5. CHECKING THE EVIDENCE FOR BIAS
    • Consider the factors that can influence the results of a study to give inaccurate conclusions using a risk of bias assessment.
    • Classify selected articles by study design.
    • Select a risk of bias assessment tool appropriate to the study design.
    • Perform risk of bias assessment** and record the results.
  6. DESCRIBING THE BODY OF EVIDENCE
    • Describe the characteristics of selected studies.
    • Perform data extraction using a pre-specified extraction form.
    • Synthesise and interpret results using qualitative or quantitative methods.
  7. ASSESSING CERTAINTY OF EVIDENCE
    • Assess the certainty of the evidence to provide information on the reliability and accuracy.
    • Prepare ‘summary of findings’ tables and create an evidence profile for each research question.
    • Assess certainty of evidence using GRADE.***
    • Consider overall certainty of evidence.
  8. PRESENTING RESULTS AND REPORTING
    • Prepare reports including evidence searching results, results of selection and summary of outcomes.
    • Present or report to related group or committee.
    • Apply the GRADE public health framework to assist in developing public health recommendations from the evidence.
* PI/ECO—Population, Intervention/Exposure, Comparison, Outcomes
** This step may involve two investigators performing independently and reaching consensus or may be conducted by a single investigator with a second investigator validating the outcomes.
*** GRADE—The Grading of Recommendations Assessment, Development and Evaluation The process for developing clinical guidelines may vary.