Table 1.

Steps in performing a systematic review and meta-analysis

Stage	Task
Step 1	Formulate the research question.
Step 2	Develop the a priori study protocol and work schedule and register and publish it online at the International Prospective Register of Systematic Reviews (PROSPERO register).
Step 3	Begin the organized search and archiving of available literature, using translation where necessary to include publications not in English (this was important for schistosomiasis because of the large number of publications in Chinese, Portuguese, and French). Searches must also seek for “gray literature,” which are data resources in official reports or other publications not found in scientific journals. Researchers should similarly look for materials such as book chapters that may contain relevant data but are not indexed in online systems. The project should request and keep on file scans of articles not immediately available in electronic versions.
Step 4	After exhaustive searching by topic, titles, and abstracts of recovered materials are reviewed to determine their likelihood of having usable data for meta-analysis. Promising articles are then read in full and data reviewed (with checks for non-duplication, human focus, and target population relevance) in sufficient detail to be included in the analysis.
Step 5	Data extracted are curated in a searchable database including relevant information on study design, populations, locations, interventions, etc.
Step 6	Summary statistics are generated for the study outcomes of interest. Assessment of heterogeneity across studies is then performed, and where appropriate, random effects modeling is used to provide the summary estimates of effect sizes in outcomes. There should be sensitivity analysis by subgroup, including assessment of risk of study bias.
Step 7	Presentation and publication of results are required. Updates to protocol registration are carried out to indicate completion and archiving of data used in the meta-analysis.