Fair Inference On Outcomes

In this paper, we consider the problem of fair statistical inference involving outcome variables. Examples include classification and regression problems, and estimating treatment effects in randomized trials or observational data. The issue of fairness arises in such problems where some covariates or treatments are "sensitive," in the sense of having potential of creating discrimination. In this paper, we argue that the presence of discrimination can be formalized in a sensible way as the presence of an effect of a sensitive covariate on the outcome along certain causal pathways, a view which generalizes (Pearl, 2009). A fair outcome model can then be learned by solving a constrained optimization problem. We discuss a number of complications that arise in classical statistical inference due to this view and provide workarounds based on recent work in causal and semi-parametric inference

Is Algorithmic Affirmative Action Legal?

This Article is the first to comprehensively explore whether algorithmic affirmative action is lawful. It concludes that both statutory and constitutional antidiscrimination law leave room for race-aware affirmative action in the design of fair algorithms. Along the way, the Article recommends some clarifications of current doctrine and proposes the pursuit of formally race-neutral methods to achieve the admittedly race-conscious goals of algorithmic affirmative action. The Article proceeds as follows. Part I introduces algorithmic affirmative action. It begins with a brief review of the bias problem in machine learning and then identifies multiple design options for algorithmic fairness. These designs are presented at a theoretical level, rather than in formal mathematical detail. It also highlights some difficult truths that stakeholders, jurists, and legal scholars must understand about accuracy and fairness trade-offs inherent in fairness solutions. Part II turns to the legality of algorithmic affirmative action, beginning with the statutory challenge under Title VII of the Civil Rights Act. Part II argues that voluntary algorithmic affirmative action ought to survive a disparate treatment challenge under Ricci and under the antirace-norming provision of Title VII. Finally, Part III considers the constitutional challenge to algorithmic affirmative action by state actors. It concludes that at least some forms of algorithmic affirmative action, to the extent they are racial classifications at all, ought to survive strict scrutiny as narrowly tailored solutions designed to mitigate the effects of past discrimination

The Measure and Mismeasure of Fairness: A Critical Review of Fair Machine Learning

The nascent field of fair machine learning aims to ensure that decisions guided by algorithms are equitable. Over the last several years, three formal definitions of fairness have gained prominence: (1) anti-classification, meaning that protected attributes---like race, gender, and their proxies---are not explicitly used to make decisions; (2) classification parity, meaning that common measures of predictive performance (e.g., false positive and false negative rates) are equal across groups defined by the protected attributes; and (3) calibration, meaning that conditional on risk estimates, outcomes are independent of protected attributes. Here we show that all three of these fairness definitions suffer from significant statistical limitations. Requiring anti-classification or classification parity can, perversely, harm the very groups they were designed to protect; and calibration, though generally desirable, provides little guarantee that decisions are equitable. In contrast to these formal fairness criteria, we argue that it is often preferable to treat similarly risky people similarly, based on the most statistically accurate estimates of risk that one can produce. Such a strategy, while not universally applicable, often aligns well with policy objectives; notably, this strategy will typically violate both anti-classification and classification parity. In practice, it requires significant effort to construct suitable risk estimates. One must carefully define and measure the targets of prediction to avoid retrenching biases in the data. But, importantly, one cannot generally address these difficulties by requiring that algorithms satisfy popular mathematical formalizations of fairness. By highlighting these challenges in the foundation of fair machine learning, we hope to help researchers and practitioners productively advance the area

FairCanary: Rapid Continuous Explainable Fairness

Machine Learning (ML) models are being used in all facets of today's society to make high stake decisions like bail granting or credit lending, with very minimal regulations. Such systems are extremely vulnerable to both propagating and amplifying social biases, and have therefore been subject to growing research interest. One of the main issues with conventional fairness metrics is their narrow definitions which hide the complete extent of the bias by focusing primarily on positive and/or negative outcomes, whilst not paying attention to the overall distributional shape. Moreover, these metrics are often contradictory to each other, are severely restrained by the contextual and legal landscape of the problem, have technical constraints like poor support for continuous outputs, the requirement of class labels, and are not explainable. In this paper, we present Quantile Demographic Drift, which addresses the shortcomings mentioned above. This metric can also be used to measure intra-group privilege. It is easily interpretable via existing attribution techniques, and also extends naturally to individual fairness via the principle of like-for-like comparison. We make this new fairness score the basis of a new system that is designed to detect bias in production ML models without the need for labels. We call the system FairCanary because of its capability to detect bias in a live deployed model and narrow down the alert to the responsible set of features, like the proverbial canary in a coal mine

Abstracting Fairness: Oracles, Metrics, and Interpretability

It is well understood that classification algorithms, for example, for deciding on loan applications, cannot be evaluated for fairness without taking context into account. We examine what can be learned from a fairness oracle equipped with an underlying understanding of ``true'' fairness. The oracle takes as input a (context, classifier) pair satisfying an arbitrary fairness definition, and accepts or rejects the pair according to whether the classifier satisfies the underlying fairness truth. Our principal conceptual result is an extraction procedure that learns the underlying truth; moreover, the procedure can learn an approximation to this truth given access to a weak form of the oracle. Since every ``truly fair'' classifier induces a coarse metric, in which those receiving the same decision are at distance zero from one another and those receiving different decisions are at distance one, this extraction process provides the basis for ensuring a rough form of metric fairness, also known as individual fairness. Our principal technical result is a higher fidelity extractor under a mild technical constraint on the weak oracle's conception of fairness. Our framework permits the scenario in which many classifiers, with differing outcomes, may all be considered fair. Our results have implications for interpretablity -- a highly desired but poorly defined property of classification systems that endeavors to permit a human arbiter to reject classifiers deemed to be ``unfair'' or illegitimately derived.Comment: 17 pages, 1 figur