Table 1.

Precision input value for structure with evidence available for all contrasts.

(a) Evidence scenario and description		(b) Precision (variance) input by level of evidence			(c)${\widehat{V}}_{\mathrm{AB}}$obtained for an IC using values in (b)
Scenario	Description	Direct A vs. B (Fig. 1A)	All first-order indirect (Fig. 1D)	All second-order indirect (Fig. 1F)	Direct evidence	First-order IC	Second-order IC
1	Evidence available in equal amounts for all comparisons	P = 1 (V = 1)	P = 1 (V = 1)	P = 1 (V = 1)	1	2	3
2	Sparse network; a few small trials/weak evidence available for direct and first order. Stronger evidence for second order	P = 0.5 (V = 2)	P = 0.75 (V = 1.33)	P = 1 (V = 1)	2	2.66	3.66
3	Few trials/weak direct evidence on focal treatments. More evidence for first- and second-order comparisons	P = 0.5 (V = 2)	P = 2 (V = 0.5)	P = 5 (V = 0.2)	2	1	1.2
4	Strong direct evidence available for focal treatments. All other evidence weaker	P = 5 (V = 0.2)	P = 2 (V = 0.5)	P = 1 (V = 1)	0.2	1	2
5	Well-populated network; several trials. Strong evidence available for each comparison	P = 5 (V = 0.2)	P = 3 (V = 0.33)	P = 3 (V = 0.33)	0.2	0.66	0.99

Notes. Evidence scenarios and corresponding precision input values for each level of evidence in the six-treatment network. “All first-order indirect” refers to evidence on a treatment contrast that contributes to a first-order IC, i.e., A vs. C, …, B vs. F. The variance ${\stackrel{⌢}{V}}_{\mathrm{AB}}^{\mathrm{I}}$ for a first-order IC is formed, e.g., ${\stackrel{⌢}{V}}_{\mathrm{AB}}^{\mathrm{I}}={\stackrel{⌢}{V}}_{\mathrm{AC}}^{\mathrm{D}}+{\stackrel{⌢}{V}}_{\mathrm{BC}}^{\mathrm{D}}$ “All second-order indirect” refers to evidence on a treatment contrast that contributes to a second-order IC, i.e., C vs. D, …, E vs. F. The variance ${\stackrel{⌢}{V}}_{\mathrm{AB}}^{\mathrm{I}}$ for a second-order IC is formed, e.g., ${\stackrel{⌢}{V}}_{\mathrm{AB}}^{\mathrm{I}}={\stackrel{⌢}{V}}_{\mathrm{AD}}^{\mathrm{D}}+{\stackrel{⌢}{V}}_{\mathrm{CD}}^{\mathrm{D}}+{\stackrel{⌢}{V}}_{\mathrm{BC}}^{\mathrm{D}}$.

IC, indirect comparison; P, precision; V, variance.