By Eric S. Maskin, 2007 Nobel Laureate in Economic Sciences, Adams University Professor at Harvard University, and Co-President of the Society for the Analysis of Government and Economics (SAGE)
  Feb 25, 2025 — Journal of Political Economy, Vol. 133, No. 2 (Journal Article)

ABSTRACT: We argue that Arrow’s independence of irrelevant alternatives (IIA) condition is unjustifiably stringent because it rules out making a social welfare function sensitive to individuals’ preference intensities. Accordingly, we propose a modified version of IIA, MIIA, that is a necessary and sufficient relaxation of IIA for taking account of intensities. Rather than obtaining an impossibility result, we show that MIIA together with several other axioms (satisfied by virtually all voting rules and social welfare functions used in practice and studied in theory) uniquely characterizes the Borda count (sometimes called rank-order voting) as a social welfare function.

Read More: https://scholar.harvard.edu/maskin/publications/arrows-theorem-mays-axiom-bordas-rule