Evaluating heterogeneous brokerage: New conceptual and methodological approaches and their application to multi-level environmental governance networks

We present two new approaches for assessing the relative contributions of different types of actors to heterogeneous brokerage in networks. These approaches distinguish between the tendency of certain types of actors to (1) mediate between dissimilar actors (heterogeneous brokerage “activity”), and (2) be the sole mediators between dissimilar actors (“exclusivity”). We present methods for implementing these approaches, using baseline models of tie formation and node removal, respectively. To illustrate the value of both approaches, independently and in combination, we apply them to evaluate horizontal and vertical heterogeneous brokerage in two environmental governance networks. Our analysis reveals certain types of actors with high heterogeneous brokerage activity but low exclusivity (and vice versa), which has important implications for governance processes and outcomes. Likewise, results show many similarities across the evaluated networks, but also some notable differences, suggesting that the incentives and constraints for heterogeneous brokerage vary not only by actor type, but also by network-level contextual differences.