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18 J. Legal Analysis 1 (2026)

handle is hein.journals/jlegan18 and id is 1 raw text is: 


Journal of Legal Analysis, 2026, 18, 1-18


                                                                    https://doi.org/10.1093/jIa/laaf0l3
                                                                                            Article








Differential validity in fair lending

Spencer  Carol, Talia Gillis  *, Scott Nelson3

'Independent, United States of America
2Law, Columbia University, United States of America
Finance, The University of Chicago Booth School of Business, United States of America
*Corresponding author. Talia Gillis, Law, Columbia University, 435 west 116th Street, New York, NY 10027.
E-mail: tbg2117@columbia.edu



Abstract
Fair lending's disparate impact doctrine aims to address lending disparities. But which disparities?
Traditional fair lending has narrowly focused  on equal  outcomes-examining differences in loan
approval rates or interest rates. However, this singular focus overlooks other dimensions of disparities
that are essential for fair credit access. This article challenges the conventional emphasis on equal
outcomes,  demonstrating  how  it has failed to address deep-rooted inequalities in traditional credit
allocation while also stifling innovation in machine-learning and  alternative data. We argue that
disparities in the validity of creditworthiness predictions-the accuracy with which a model identifies
creditworthy applicants-importantly  impact equal access to credit and, in particular, the extension of
credit to the creditworthy. Despite mounting empirical evidence of the harm  of validity disparities,
traditional fair lending enforcement inadequately  recognizes this disparity dimension, a gap that
may  become  increasingly harmful as lending decisions rely on advanced statistical methods. Future
regulatory guidance, enforcement,  and supervision  should explicitly recognize validity inequalities
across protected groups while addressing the accompanying   challenges of this more comprehensive
perspective on disparities, which is essential for equitable credit allocation.



1.   INTRODUCTION
There is emerging consensus  that antidiscrimination law is in urgent need of reform (e.g. Barocas and
Selbst 2016; Kim 2017; Huq 2019; Ho and Xiang 2020; Yang and Dobbie 2020; Gillis 2022; Kim 2022; Starr
2023). Whether  due to the increasing use of alternative data (Kaul 2021) or machine-learning tools
(FinRegLab 2021), fair lending's disparate impact framework is ill-equipped to achieve fair outcomes
in modern  underwriting  (Gillis and Spiess 2019; Aggarwal 2021; Hurlin et al. 2024; Sargeant 2023).
At the same  time, the algorithmic fairness literature, originating in computer science and statistics,
has highlighted the many  ways statistical predictions can result in and perpetuate disparities across
groups  (Dwork et al. 2012; Hardt, Price and Srebro 2016; Kusner et al. 2017; Chen et al. 2019), as well
as the inherent tensions between competing  fairness definitions (Chouldechova 2017; Kleinberg et al.
2017; Friedler et al. 2021). However, much of this literature remains disconnected from the practical
realities of specific decision-making contexts, particularly fair lending, and rarely addresses how law




© The Author(s) 2026. Published by Oxford University Press.
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