To do so the network without the test set was fitted to the degree-corrected, non-overlapping, nested blockmodel and the description length minimised using the function implemented in graph-tool. Then 10,000 sweeps were carried out using the MCMC algorithm implemented in graph-tool, collecting the log-likelihood of 𝑃(𝑨+𝛿𝑨|{𝒃 𝑙 }) 𝑃(𝑨|{𝒃 𝑙 }) for each edge in the test set as outlined under "Link Prediction". The log-likelihoods were then averaged and the likelihood ratios for the different edges found.