Figure 1

Search method (numbered arrow 1) and streaming (arrow 2) of systematic reviews, screening (arrow 3, 4 & 5) and classification (arrow 6) of eligible studies, and decant and analytic plan (arrow 7) of component groups being control (rectangles) and intervention (ovals) groups from studies of VAP prevention methods and a reference category of observation (diamond) groups from cohorts of ICU patients without a pneumonia prevention method under study. Dotted rectangles and ovals represent component groups within studies of antibiotic based methods of VAP prevention (SDD) which received protocolized parenteral antibiotic prophylaxis. Analytic plan; the vertical dotted lines connecting the component groups represent the group contrasts used towards the calculation of the counterfactual effects and the horizontal dotted rectangles represent the calibrations used toward the estimation of contextual effects among the component groups referent to the observation groups. Note; the total numbers do not tally as some systematic reviews provided studies in more than one category and some studies provided groups in more than one category.