Big & rich: A new way to measure attention and participation diversity.

Policy process scholars often are interested in the relative diversity or concentration of attention across issues, or the relative participation of different groups and information sources within an issue domain or policy venue. Are policymakers devoting lots of attention to a small set of issues or dividing their attention more evenly across a larger agenda? Are a few groups dominating deliberation or is participation more evenly distributed among actors? The Shannon's H measure of information entropy has become the most common measure of diversity or concentration of attention and participation, with higher values indicating a relatively more diverse issue agenda and lower values indicating more concentration or less entropy. Many possible combinations of categories and the proportions of observations within those categories can produce statistically‐indistinguishable values, which makes Shannon's H less informative than we might like. This research note proposes new measures of richness and evenness to capture both the breadth and relative spread of attention or participation. The note provides examples of how to measure and visualize richness and evenness of attention across policy actors, the richness and evenness of actors across issues, and richness and evenness across time. [ABSTRACT FROM AUTHOR]