Figure 1
From: NBIA: a network-based integrative analysis framework – applied to pathway analysis

The overall pipeline of NBIA. The input consists of m independent datasets and n genes. Step (1): calculate effect size (Hedge’s g) for each gene in each study. Step (2): combine effect sizes for each gene across multiple studies using the REstricted Maximum Likelihood (REML) algorithm. Step (3): compute the z-score (\({z}_{i}=\frac{{\mu }_{i}}{{\sigma }_{i}}\)) and calculate the left- and right-tailed p-values (epil and epir) using the standard normal distribution. This ends the first module. Step (4): perform hypothesis testing at gene level using empirical Bayesian statistics. For gene ith and dataset jth, the left- and right-tailed p-values obtained from the Bayesian test are bpijl and bpijr. Step (5): combine the one-tailed p-values for each gene, i.e., bpil = addCLT(bpi1l, …, bpiml) and bpir = addCLT(bpi1r, …, bpimr). This ends the second module. Step (6): combine Bayesian p-values with the p-values of the effect size using maxP, i.e. pil = max(epil, bpil) and pir = max(epir, bpir). Step (7): choose genes that are significantly impacted from both hypothesis testing and effect size perspectives using FDR-adjusted p-values (1% threshold by default). This ends the third module. Step (8): compute the perturbation factors for NBIA-prioritized genes and pathways. Step (9): identify impacted pathways using impact analysis.