Five illustrative network meta-analyses with net heat plot. In a) to e), the network design is shown on the left: six treatments and six, eight or fifteen different observed designs based on two-armed studies. The nodes are placed on the circumcircle and are labeled according to the treatments. The edges show which treatments are directly compared. The thickness of an edge represents the inverse standard error , which is equal one for all designs. We introduced inconsistency by perturbing the effect of one edge (marked in red) by five standard errors of the direct effect estimate. The corresponding net heat plots are shown on the right side: The area of the gray squares displays the contribution of the direct estimate in design d (shown in the column) to the network estimate in design d’ (shown in the row). The colors are associated with the change in inconsistency between direct and indirect evidence in design d’ (shown in the row) after detaching the effect of design d (shown in the column). Blue colors indicate an increase and warm colors indicate a decrease (the stronger the intensity of the color, the stronger the change).
Krahn et al. BMC Medical Research Methodology 2013 13:35 doi:10.1186/1471-2288-13-35