Comparing measures of political similarity: An empirical comparison of S versus τb in the study of international conflict

D. Scott Bennett, Matthew C. Rupert

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Signorino and Ritter developed and advocated a new measure of the political similarity of states (S). They demonstrated logical flaws associated with the common Kendall’s τb-based alliance similarity measure and showed that using S may yield quite different similarity estimates. But without a broader empirical comparison and analysis using S, the full empirical ramifications of this difference is not known. In this study, a comparison of S versus τb is conducted over a wide spatial and temporal domain, examining the relationship between S, τb, expected utility scores, and conflict. Despite significant positive correlations, important differences in the distribution of S and τb-based measures of alliance similarity are found. It should not be assumed that the measures are substitutable. Reanalysis of an important expected utility theory of war shows a stronger relationship between equilibrium predictions and conflict when S is used versus τb.

Original languageEnglish (US)
Pages (from-to)367-393
Number of pages27
JournalJournal of Conflict Resolution
Issue number3
StatePublished - Jun 2003

All Science Journal Classification (ASJC) codes

  • Business, Management and Accounting(all)
  • Sociology and Political Science
  • Political Science and International Relations

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