The Effect of the Rooney Rule on Implicit Bias in the Long Term

Abstract

The Rooney Rule, originally proposed to counter implicit bias in hiring, has been implemented in the private and public sector in various settings. This rule requires that a decision-maker include at least one candidate from an underrepresented group in their shortlist of candidates. Recently, [42] proposed a mathematical model of implicit bias and studied the effectiveness of the Rooney Rule when applied to a single selection decision. However, selection decisions often occur repeatedly over time; e.g., a software firm is continuously hiring employees or a university makes admissions decisions every year. Further, it has been observed that, given consistent counterstereotypical feedback, implicit biases against underrepresented candidates can change. In this paper, we propose a model of how a decision-maker's implicit bias changes over time given their hiring decisions either with or without the Rooney Rule in place. Our model draws from the work of [42] and the literature on opinion dynamics. Our main result is that, for this model, when the decision-maker is constrained by the Rooney Rule, their implicit bias roughly reduces at a rate that is inverse of the size of the shortlist---independent of the total number of candidates, whereas without the Rooney Rule, the rate is inversely proportional to the number of candidates. Thus, our model predicts that when the number of candidates is much larger than the size of the shortlist, the Rooney Rule enables a significantly faster reduction in implicit bias, providing additional reason in favor of instating it as a strategy to mitigate implicit bias. Towards empirically evaluating the long-term effect of the Rooney Rule in repeated selection decisions, we conduct an iterative candidate selection experiment on Amazon Mechanical Turk. We observe that, indeed, decision-makers subject to the Rooney Rule select more minority candidates in addition to those required by the rule itself than they would if no rule is in effect, and in fact are able to do so without considerably decreasing the utility of candidates selected.