Figure 6. Average HR as a function of centrality measures for the preferential attachment network.

There is an increasing trend between treatment success and the measures of betweenness and closeness (a, b), which implies that treatment success is not only a function of connectivity but also a function of node centrality and ease of access to relevant information. However, there is a decreasing trend between treatment success and local clustering coefficient (c). We speculated that nodes with high clustering coefficient are those which tend to interact within a closed group of trials (“silos” of information exchange) and consequently are the least successful.