Table 3.

Next steps by systematic review framework step

Framework step	Next steps (final products: handbook and reporting guidelines)
Specify research question	• Improvement of research question formulation
Protocol	• Template for protocols for systematic reviews of studies of prevalence of exposure • Publication of protocols in a peer-reviewed journal
Systematic search	• Development of standard search strings and specialized search filters • Identification and development of specific academic and grey literature databases to search • Guidance on including modelling versus empirical data • Automated updating of searches
Defining eligibility criteria and screening studies	• Guidance to help reviewers produce eligibility criteria that are sufficiently detailed on exposure measurements and methods
Data extraction	• Template for extracting data from studies of prevalence of exposure • Guidance to include information on specific types of bias for which to extract data (e.g., numerator-denominator bias)
Risk of bias assessment	• Testing and further development of RoB-SPEO (more details in [10])
Synthesis	• Guidance on what evidence should be pooled and what should not (quantitative meta-analysis versus narrative synthesis) • Guidance on how to pool skewed data, with ceiling and floor (0 and 100% exposed), including which software to use • Guidance on interpreting pooled prevalence estimates, including model heterogeneity and skewed pooled confidence intervals
Certainty of body of evidence assessment	• Testing and further development of QoE-SPEO (more details in [8])