Measures or indices to quantify elections’ disproportionality have been widely proposed in literature and used extensively to analyse and compare election results. This study introduces the Unfairness Index (UI) as a generalised versatile easy-to-use disproportionality index. UI satisfies 11 out of 11 criteria proposed by Taapegara and Grofman (2003), which are considered desirable for any disproportionality index, and thus it scores higher than the scores of Loosemane-Hanby Index (LHI) and Galleger Index (GhI). UI is bound between 0 and 1 (0 and 100%), with 0 indicates no disproportionality. Applying UI to elections in the UK and ten other countries for the period 1979-2011 established that UI not only agrees with LHI and GhI in its assessment regarding election disproportionality, it also interprets better the unfairness in an election compared to LHI and GhI.

Download the full article: Measuring Election Fairness: A New Approach