Group Inequalities and ‘Scanlan’s Rule’: Two Apparent Conundrums and How We Might Address Them

In situations where an adverse social outcome affects disadvantaged and advantaged groups in society differently, the rates at which those groups experience favorable or adverse outcomes tend to be systematically related to the overall prevalence of the outcome. Specifically, as the overall prevalence of that outcome reduces (e.g. as a result of a policy measure or social improvement), the adverse outcome may be found to reduce proportionately less among the group with the higher baseline rate (call it the “disadvantaged” group), while concomitantly the rate of escaping the unfavorable outcome rises proportionately less in the other (“advantaged”) group. The propensity for this to happen was first noticed by James P. Scanlan, and is sometimes referred to as ‘Scanlan's Rule’. The Rule might be seen as calling into question standard measurement devices for characterizing groups as being relatively disadvantaged or advantaged, and as suggesting that a concern for group inequality could stymie the possibility of social progress. This paper seeks to address these questions, and in so doing suggests that Scanlan’s Rule and its widespread occurrence across a number of social situations deserve to be acknowledged. However, it also suggests that the disturbing implications of the Rule alluded to earlier are probably unfounded, and that the Rule only bolsters the case for affirmative action in a variety of instances of group inequality.