“…Then the prominent measurement approach based on quantile-preserving spreads, chiefly median-preserving spreads, is described in detail, crucially distinguishing between explicit and implicit quantiles, as well as between inequality and bipolarisation concepts (works reviewed include Mendelson, 1987;Apouey, 2007;Abul Naga and Yalcin, 2008;Lazar and Silber, 2013;Kobus, 2015;Chakravarty and Maharaj, 2015). Drawing from Sarkar and Santra (2020), a special subsection explains proposals to measure inequality and bipolarisation when distributions do not share quantiles of interest (e.g. the median).…”