Equalizing Credit Opportunity in Algorithms Aligning Algorithmic Fairness Research with U.S. Fair Lending Regulation_2

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Equalizing Credit Opportunity in Algorithms: Aligning
Algorithmic Fairness Research with U.S. Fair Lending Regulation
I. Elizabeth Kumar
Brown University
USA
iekumar@brown.edu
Keegan E. Hines
Arthur AI
USA
keegan@arthur.ai
John P. Dickerson
Arthur AI
USA
john@arthur.ai
ABSTRACT
Credit is an essential component of nancial wellbeing in America,
and unequal access to it is a large factor in the economic dispari-
ties between demographic groups that exist today. Today, machine
learning algorithms, sometimes trained on alternative data, are in-
creasingly being used to determine access to credit, yet research has
shown that machine learning can encode many dierent versions
of “unfairness,” thus raising the concern that banks and other nan-
cial institutions could—potentially unwittingly—engage in illegal
discrimination through the use of this technology. In the US, there
are laws in place to make sure discrimination does not happen
in lending and agencies charged with enforcing them. However,
conversations around fair credit models in computer science and
in policy are often misaligned: fair machine learning research of-
ten lacks legal and practical considerations specic to existing fair
lending policy, and regulators have yet to issue new guidance on
how, if at all, credit risk models should be utilizing practices and
techniques from the research community. This paper aims to better
align these sides of the conversation. We describe the current state
of credit discrimination regulation in the United States, contextu-
alize results from fair ML research to identify the specic fairness
concerns raised by the use of machine learning in lending, and
discuss regulatory opportunities to address these concerns.
CCS CONCEPTS
Computing methodologies Machine learning
;
Applied
computing Law, social and behavioral sciences.
ACM Reference Format:
I. Elizabeth Kumar, Keegan E. Hines, and John P. Dickerson. 2022. Equalizing
Credit Opportunity in Algorithms: Aligning Algorithmic Fairness Research
with U.S. Fair Lending Regulation. In Proceedings of the 2022 AAAI/ACM
Conference on AI, Ethics, and Society (AIES’22), August 1–3, 2022, Oxford,
United Kingdom. ACM, New York, NY, USA, 12 pages. https://doi.org/10.
1145/3514094.3534154
INTRODUCTION
Credit is an essential component of nancial well-being for Ameri-
cans, and unequal access to it is a signicant factor in the economic
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AIES’22, August 1–3, 2022, Oxford, United Kingdom
©2022 Copyright held by the owner/author(s). Publication rights licensed to ACM.
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https://doi.org/10.1145/3514094.3534154
disparities between demographic groups that exist today. For this
reason, it is critical to make sure the American lending ecosys-
tem is free of discrimination. In America, there are laws in place
which specically ban discrimination in lending, as well as agen-
cies charged with enforcing them. Today, machine learning (ML)
algorithms (sometimes trained on “nontraditional” data) are increas-
ingly being used to allocate access to credit. A vast body of research
has demonstrated that ML algorithms can encode many dierent
versions of “unfairness,” thus raising the concern that banks and
other nancial institutions could—potentially unwittingly–engage
in illegal discrimination through the use of this technology.
The nebulous threat of “algorithmic discrimination” poses a
challenge to federal regulators, who must decide how, if at all, to
update their enforcement practices or issue new guidance in light
of these concerns [
74
], which are often articulated by computer
scientists in the abstract and not in terms of the actual practices,
data, and algorithms used in this sector. Meanwhile, without specic
guidance from regulators, researchers and practitioners who want
to study or apply fair ML in this particular setting lack a clear
picture of the kinds of tools and metrics that will be useful, legal,
and practical for detecting and correcting unfairness in algorithms
in this setting. For these reasons, this paper aims to orient the
conversation around fair ML research in the context of predicting
credit risk from both perspectives.
In Section 1, we briey describe the state of American fair lend-
ing regulation and analyze recent messaging from certain federal
agencies on the threat of algorithmic discrimination. In Section 2,
we discuss methods proposed by the ML community to measure un-
fairness in algorithms, and determine the extent to which they may
relate to the principles of the Equal Credit Opportunity Act (ECOA)
and the goals of the federal agencies discussed above. Keeping these
metrics in mind, we contextualize results from fair ML research
in the consumer credit setting, and identify specic fair lending
risks throughout dierent parts of a machine learning system’s
development. By analyzing how these mechanisms are likely to
play out in the credit setting, we can be more specic about the
kinds of problems regulators should anticipate and address, rather
than repeating the folk wisdom of "bias in, bias out." Finally, in
Section 3, we discuss specic opportunities for regulators to use
their authority to encourage fair ML practices.
1 CREDIT DISCRIMINATION REGULATION
IN THE UNITED STATES
In this section, we provide a background on the laws and policies
which regulate anti-discrimination in consumer credit. We further
set the stage for the conversation about algorithmic discrimination
by identifying specic comments and actions from federal agencies
arXiv:2210.02516v1 [cs.LG] 5 Oct 2022
signifying their willingness to tackle the issue of discrimination in
algorithms.
1.1 Fair lending legislation
1.1.1 Anti-discrimination legislation. The issue of discrimination
in credit lending decisions is not novel to the algorithmic setting.
While lending has been around for centuries, Americans increas-
ingly began to rely on consumer credit to nance large purchases
in the 1950’s and 60’s [
81
]. During this period, individual loan o-
cers and specialists were ultimately responsible for the subjective
determination of whether a loan applicant was creditworthy; nu-
merical methods for estimating credit risk existed but were not
widely or systematically used [
28
]. This presented a risk of in-
tentional discrimination due to personal bias. Additionally, some
codied lending policies in eect at the time clearly disadvantaged
women and minorities. During congressional hearings, testimonies
cited practices such as requiring single women to provide a male
co-signer for a mortgage loan [40, 81].
In the spirit of implementing ideas from the civil rights legislation
of the 60’s, which did not directly address lending, ECOA was
passed in 1974 to ensure that all Americans were treated fairly in
a system that determined so much of their economic success. It
prohibits creditors from “discriminat[ing] against any applicant,
with respect to any aspect of a credit transaction on the basis of
race, color, religion, national origin, sex or marital status,” among
other factors [
87
]. The law applies to any organization that extends
credit, including loans and credit cards.
The Fair Housing Act, also known as Title VIII of the Civil Rights
Act of 1968, prohibits discrimination in housing on the basis of sev-
eral protected characteristics, and applies to mortgage providers.
The U.S. Department of Housing and Urban Development (HUD) en-
forces the Fair Housing Act, and has specied narrow rules making
disparate impact litigation dicult; partly because of this, mortgage
algorithms are not our main focus in this paper.
1.1.2 Data collection rules. At the time of its passing, the ECOA
gave the Board of Governors of the Federal Reserve Board (FRB)
rulemaking authority to implement the law; this set of rules is
known as Regulation B. Regulation B specically prohibits the
collection of information about protected characteristics: "A creditor
shall not inquire about the race, color, religion, national origin, or
sex of an applicant or any other person in connection with a credit
transaction" [
80
]. Credit transactions, here, can include things like
consumer credit, business credit, mortgage loans, and renancing.
A glaring set of exceptions to this rule are in cases where the
Home Mortgage Disclosure Act (HMDA) applies. Passed in 1975, the
act requires certain nancial institutions to provide mortgage data
to the public, and in particular requires lenders to collect and report
race and gender information of mortgage applications. The act was
drafted in response to the practice of redlining, in which lenders
would explicitly identify geographic regions and neighborhoods
that they would not lend to because they were inhabited by people
of color. This information is used to identify indicators of mortgage
discrimination and encourage lenders to comply with ECOA [84].
In the non-mortgage setting, Regulation B contains an additional
exception to the ban on collecting protected characteristics: when
the information is explicitly collected for self-testing, which is
dened as any inquiry “designed and used specically to determine
the extent or eectiveness of a creditor’s compliance with the Act”
[
80
]. In doing so, lenders must make it clear to the applicant that
providing the information is voluntary. However, this practice is
very uncommon; Slaughter et al
. [83]
speculate that this is because
of a "fear that their collection of the data will validate or exacerbate
claims that their decisions are biased." Self-testing might also be
disincentivized if corporations believe that the data itself would
ultimately benet plaintis in a potential disparate impact suit.
It may seem counter-intuitive that HMDA requires the collection
of sensitive information while ECOA bans it. In fact, both HMDA’s
requirement for collecting sensitive information and ECOA’s ban
on it are controversial. Some argue that the existence of HMDA
provides an important basis of evidence for lawsuits or that the pol-
icy itself caused lenders to curb their own discriminatory practices,
and thus a similar provision should be in place for non-mortgage
lenders [
4
,
14
,
23
,
84
]. Others, especially banks, have argued that
HMDA is unfair, costly, and leads to false accusations of illegal
discrimination [54].
The Federal Reserve Board, which was responsible for enforcing
ECOA until the Consumer Financial Protection Bureau (CFPB) was
established, has considered removing the ban on the collection of
protected information several times since the law was originally
passed. In 2003, it ultimately rejected a proposal to lift the ban
and mandate the collection of certain sensitive information [
69
].
The rst reason it cited was the natural one: that creditors might
use this information for discriminatory purposes; however, many
members of Congress, consumer advocates and researchers found
this unconvincing [
90
]. The second was that "many creditors would
elect not to collect the data while those that did collect it would
use inconsistent standards, criteria and methods. Consequently, the
data would be of questionable utility because there would be no
assurance of its accuracy nor would there be any way to compare it
from creditor to creditor" [
84
]. The U.S. Government Accountability
Oce found in 2008 that while such a mandatory data collection
could provide benets to researchers and regulators, it could be
costly or dicult for the lenders themselves [
90
]; Bogen et al
. [14]
suggest that the failure to implement such measures has largely
been due to pressure from banks, which Taylor
[84]
found were the
overwhelming dissenting voice in responses to the FRB’s request
for comments on their proposal.
1.2 Fair lending in practice
The two major discrimination doctrines which are relevant to fair
lending law today are disparate treatment and disparate impact.
Disparate treatment applies when individuals are explicitly treated
dierently on a prohibited basis. Under disparate impact doctrine,
on the other hand, a creditor may be found to have illegally dis-
criminated against a protected class if the eect of the practice
adversely impacts that group even if the policy in question was
facially neutral. The Supreme Court has found that the disparate
impact is cognizable under the FHA [
3
], but has not made a similar
ruling about ECOA. However, the court’s language in Inclusive
Communities [
85
], relevant case law [
11
], and the CFPB’s ocial
interpretation of Regulation B [
18
] all support the general consen-
sus that disparate impact theory is cognizable under ECOA. Federal
courts have consistently upheld this since the 1980s [23].
Plaintis usually rely on burden-shifting systems for establishing
aprima facie claim under both theories, which can then be rebut-
ted by the defendant. For a disparate treatment case, most circuit
courts have found that a modication of the McDonnell-Douglas
test, originally developed by the Supreme Court in an employment
discrimination case [
2
], can be applied to an ECOA claim–but there
is no ocial nationwide rule on the issue [
11
]. In a prima facie
disparate impact claim [
1
], a plainti must point to a specic policy
or action taken by the defendant that had a disproportionately ad-
verse impact on members of a protected class. The defendant may
respond by arguing there is a legitimate business necessity for the
policy. Then, the plainti can respond by arguing there was a less
discriminatory alternative that the defendant refused to use.
In a disparate impact claim, expert statistical testimony is neces-
sary to demonstrate that an adverse impact exists and is dispropor-
tionately felt by members of a protected class [
11
]. Again, we lack
ocial Supreme Court guidance on how exactly to go about this
under ECOA. In employment discrimination cases, however, the
ratio of the proportion of protected class that receives a favorable
outcome and the proportion of the control class is used; the oft-
cited "80% rule" is related to this statistic [
29
]. A related metric with
precedence in the credit setting is the standardized mean dierence
of outcomes for two groups [
44
]. However, it is usually insucient
to simply compare the approval rates of two groups of applicants;
since information related to creditworthiness is generally available,
higher courts generally expect that plaintis will compare the se-
lection rates of qualied applicants [
11
]. For this reason, statistical
evidence which controls for drivers of creditworthiness–such as a
conditional marginal eects test–are seen as more appropriate by
federal agencies [19].
It is dicult for plaintis to nd evidence that an individual lend-
ing decision was discriminatory, especially in the non-mortgage
setting where sensitive attribute data about applicants is generally
unavailable; some lower courts have historically acknowledged this
[
84
]. Bogen et al
. [14]
point out that "one of the few, robust public
studies on credit scores and discrimination in the United States
was performed by the FRB in 2007, at the direction of Congress.
To conduct its analysis, the FRB created a database that, for the
rst time, combined sensitive attribute data collected by the Social
Security Administration with a large, nationally representative sam-
ple of individuals’ credit records... this unusual undertaking would
not have been possible without signicant governmental time and
resources." Interestingly, the CFPB has worked around this data
limitation in some of its enforcement actions by imputing racial
information using Bayesian Improved Surname Geocoding (BISG)
to amass evidence of disparate impact [
6
]. On the other hand, in the
mortgage setting where data is available, HMDA data alone cannot
prove or disprove discrimination, and the results of discrimination
studies using HMDA data are usually contentious [75].
An important precedent is, of course, the general acceptance of
traditional credit scores as a basis of loan underwriting. Like the ma-
chine learning algorithms which are the focus of this paper, credit
scores are functions of data which are meant to provide a quantita-
tive basis on which to make a lending decision. As of yet, there have
not been successful challenges against credit scores using disparate
impact theory [
51
]. A combination of factors has contributed to this,
but one seems to be that ocial CFPB interpretations of ECOA and
OCC guidance on models are fairly generous as to what counts as
a business necessity and relation to creditworthiness, respectively
[
11
]. Further complicating this matter is the fact that creditors tend
to (credibly) argue that their scoring methods tend to expand credit
to minority applicants when compared to other methods. The FRB
bolstered the credit score’s ubiquity in their analysis of the 2007
database: they claimed that while credit scores have a “dierential
eect" [
70
], they did not "produce a disparate impact" [
7
] because
credit characteristics do not act as "proxies for race and ethnic-
ity" according to their own denition (which we will discuss the
limitations of in Section 2).
1.3 Agency communications on fair lending in
algorithms
In this section, we analyze recent messaging from several federal
agencies on the threat of algorithmic fairness in nance and credit.
These agencies are generally allowed to operate independently, but
many have been known to act cooperatively and take a unied
stance on the interpretation of the law [
77
]. The OCC, FRB, FDIC,
and CFPB recently issued a rare joint request for information re-
garding the use of articial intelligence (AI) in nancial services,
inquiring, among other things, whether banks and other interested
parties feel that additional regulatory guidance on the matter is
necessary [
74
]. Their response to the threat of algorithmic discrim-
ination will be highly inuential since, as Alex Engler has argued,
"major legislative changes to AI oversight seem unlikely in the near
future, which means that regulatory interventions will set prece-
dent for the government’s approach to protecting citizens from AI
harms" [36].
1.3.1 The Consumer Financial Protection Bureau (CFPB). The CFPB
was created by the Dodd-Frank Wall Street Reform and Consumer
Protection Act in 2011. It was designed to consolidate responsibili-
ties from several other agencies such as the Federal Reserve, FTC,
and FDIC, to write and enforce rules for both bank and non-bank
nancial institutions. It has situated itself as being well-posed to
tackle new regulatory challenges introduced by technology. The
CFPB’s internal “Oce of Competition and Innovation," dedicated
in part to addressing these challenges, has taken initiatives such as
holding tech sprints, issuing no-action letters (NALs), and develop-
ing compliance assistance sandboxes.
The most relevant action the CFPB has taken with respect to
algorithmic discrimination was its NAL to ntech lending company
Upstart in 2017. Upstart provided detailed public (and some private)
information about its underwriting process with the bureau and
requested a formal statement from the CFPB that they would not
trigger any enforcement action [
86
]. The CFPB granted the NAL.
Part of the terms of the letter stipulated that Upstart would send
the CFPB updates "regarding the loan applications it receives, how
it decides which loans to approve, and how it will mitigate risk to
consumers, as well as information on how its model expands access
to credit for traditionally underserved populations" to "further its
understanding of how these types of practices impact access to
credit generally and for traditionally underserved populations, as
摘要:

EqualizingCreditOpportunityinAlgorithms:AligningAlgorithmicFairnessResearchwithU.S.FairLendingRegulationI.ElizabethKumarBrownUniversityUSAiekumar@brown.eduKeeganE.HinesArthurAIUSAkeegan@arthur.aiJohnP.DickersonArthurAIUSAjohn@arthur.aiABSTRACTCreditisanessentialcomponentoffinancialwellbeinginAmerica...

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