The Importance of Attention Diversity and How to Measure It

Abstract

Studies of political attention often focus on attention to a single issue, such as front-page coverage of the economy. However, examining attention to a single issue without accounting for the agenda as a whole can lead to faulty assumptions. One solution is to consider the diversity of attention; that is, how narrowly or widely attention is distributed across items (e.g., issues on an agenda or, at a lower level, frames in an issue debate). Attention diversity is an important variable in its own right, offering insight into how agendas vary in their accessibility to policy problems and perspectives. Yet despite the importance of attention diversity, we lack a standard for how best to measure it. This paper focuses on the four most commonly used measures: the inverse Herfindahl Index, Shannon's H, and their normalized versions. We discuss the purposes of these measures and compare them through simulations and using three real-world datasets. We conclude that both Shannon's H and its normalized form are better measures, minimizing the danger of spurious findings that could result from the less sensitive Herfindahl measures. The choice between the Shannon's H measures should be made based on whether variance in the total number of possible items (e.g., issues) is meaningful.

Diversity in the News? A Study of Interest Groups in the Media in the UK, Spain and Denmark

“…This pattern is also evident in different levels of Shannon's H (normalized) across the three countries: for UK 0.84, Spain 0.72 and Denmark 0.80. This measure captures the diversity in attention across all groups appearing in the media and the numbers indicate that the diversity in media appearances is highest in the UK and lowest in Spain (Boydstun, Bevan & Thomas III, 2014;Halpin and Thomas III 2012).…”

Discovering Social Events through Online Attention

“…In terms of classical information theory, this can be conversely related to a measure of entropy of the discussion topics, where our results show that significant events are related to drops in the entropy (or high HHI). Entropy has been used in the past to study traditional media and online media [44]–[46]. Our results show that while the two measures are closely related, the HHI outperforms entropy as a detector of significant events.…”

Bureaucratic control and information processing: An institutional comparison

“…Lastly, we include annual measures of agenda focus of both legislative and executive agendas for Hypothesis 2. Boydstun et al () and Jennings et al () adopt the Shannon information entropy to measure how concentrated or spread out attention is. The agenda focus measure H is given as , where is the probability of topic i appearing on the policy agenda.…”