๐ค AI Summary
This study addresses the computational bottleneck in network meta-analysis arising from the reliance on matrix inversion for covariance matrix estimation. The authors propose a novel approach based on the geometric series expansion of a diffusion matrix to directly estimate the covariance matrix of treatment effects, thereby circumventing explicit matrix inversion. This method establishes, for the first time, an equivalence between the covariance structure and a random walk process on a graph, forging a theoretical link between statistical inference and network diffusion theory. The resulting algorithm substantially improves computational efficiency and is accompanied by an R package with visualization tools to facilitate interpretation and practical application of the results.
๐ Abstract
We show that the covariance matrix of the treatment effect estimates in a network meta-analysis can be obtained without matrix inversion using a geometric series of diffusion matrices. This property extends to the hat matrix and provides a connection between parameter estimation in regression analysis and random walks on the network graph. We also provide a number of visualization tools implemented in R.