Fig. 4.

Star network with six treatments when first-order indirect evidence is unavailable. Comparison of percentage increase in precision (y-axis) for treatment contrast A vs. B from expanding network of treatments under five separate scenarios over that achieved from a standard, pairwise meta-analysis. Scenarios considered under fixed- and random-effects models. Random-effects models assume “low,” “medium,” and “high” levels of heterogeneity as defined in the main text. The height of each bar denotes the percentage increase in precision of A vs. B treatment effect estimate from a network meta-analysis (NMA). The horizontal axis reports each increasing level of the network under each of the five scenarios. For graph colors: Read left to right—Each bar relates to the structure of the network in terms of which evidence is included. Scenario 1: “One trial per comparison”: Equal variance across the network. Each comparison XY represents one meta-analysis with variance equal to 1. Scenario 2: “AB weakest link, IC trials weaker”: AB comparison is the “weakest” link, with the comparisons forming ICs being weaker. Scenario 3: “AB weakest link, IC trials strong”: AB comparison is the “weakest” link, with the comparisons forming ICs being stronger. Scenario 4: “AB strongest link, IC trials weaker”: AB comparison is the “strongest” link, with the comparisons forming ICs being weaker. Scenario 5: “AB strongest link, IC trials strong”: AB comparison is the “strongest” link, with the comparisons forming ICs also being strong. IC, indirect comparision.