Theprivate and public sectors are increasingly turning to artificial intelligence (AI) systems and machine learning algorithms to automate simple and complex decision-making processes.1 The mass-scale digitization of data and the emerging technologies that use them are disrupting most economic sectors, including transportation, retail, advertising, and energy, and other areas. AI is also having an impact on democracy and governance as computerized systems are being deployed to improve accuracy and drive objectivity in government functions.
The availability of massive data sets has made it easy to derive new insights through computers. As a result, algorithms, which are a set of step-by-step instructions that computers follow to perform a task, have become more sophisticated and pervasive tools for automated decision-making.2 While algorithms are used in many contexts, we focus on computer models that make inferences from data about people, including their identities, their demographic attributes, their preferences, and their likely future behaviors, as well as the objects related to them.3
In the pre-algorithm world, humans and organizations made decisions in hiring, advertising, criminal sentencing, and lending. These decisions were often governed by federal, state, and local laws that regulated the decision-making processes in terms of fairness, transparency, and equity. Today, some of these decisions are entirely made or influenced by machines whose scale and statistical rigor promise unprecedented efficiencies. Algorithms are harnessing volumes of macro- and micro-data to influence decisions affecting people in a range of tasks, from making movie recommendations to helping banks determine the creditworthiness of individuals.4 In machine learning, algorithms rely on multiple data sets, or training data, that specifies what the correct outputs are for some people or objects. From that training data, it then learns a model which can be applied to other people or objects and make predictions about what the correct outputs should be for them.5
However, because machines can treat similarly-situated people and objects differently, research is starting to reveal some troubling examples in which the reality of algorithmic decision-making falls short of our expectations. Given this, some algorithms run the risk of replicating and even amplifying human biases, particularly those affecting protected groups.6 For example, automated risk assessments used by U.S. judges to determine bail and sentencing limits can generate incorrect conclusions, resulting in large cumulative effects on certain groups, like longer prison sentences or higher bails imposed on people of color.
With algorithms appearing in a variety of applications, we argue that operators and other concerned stakeholders must be diligent in proactively addressing factors which contribute to bias. Surfacing and responding to algorithmic bias upfront can potentially avert harmful impacts to users and heavy liabilities against the operators and creators of algorithms, including computer programmers, government, and industry leaders. These actors comprise the audience for the series of mitigation proposals to be presented in this paper because they either build, license, distribute, or are tasked with regulating or legislating algorithmic decision-making to reduce discriminatory intent or effects.
Our research presents a framework for algorithmic hygiene, which identifies some specific causes of biases and employs best practices to identify and mitigate them. We also present a set of public policy recommendations, which promote the fair and ethical deployment of AI and machine learning technologies.
This paper draws upon the insight of 40 thought leaders from across academic disciplines, industry sectors, and civil society organizations who participated in one of two roundtables.8 Roundtable participants actively debated concepts related to algorithmic design, accountability, and fairness, as well as the technical and social trade-offs associated with various approaches to bias detection and mitigation.
Our public policy recommendations include the updating of nondiscrimination and civil rights laws to apply to digital practices, the use of regulatory sandboxes to foster anti-bias experimentation, and safe harbors for using sensitive information to detect and mitigate biases. We also outline a set of self-regulatory best practices, such as the development of a bias impact statement, inclusive design principles, and cross-functional work teams. Finally, we propose additional solutions focused on algorithmic literacy among users and formal feedback mechanisms to civil society groups.
The next section provides five examples of algorithms to explain the causes and sources of their biases. Later in the paper, we discuss the trade-offs between fairness and accuracy in the mitigation of algorithmic bias, followed by a robust offering of self-regulatory best practices, public policy recommendations, and consumer-driven strategies for addressing online biases. We conclude by highlighting the importance of proactively tackling the responsible and ethical use of machine learning and other automated decision-making tools.
Algorithmic bias can manifest in several ways with varying degrees of consequences for the subject group. Consider the following examples, which illustrate both a range of causes and effects that either inadvertently apply different treatment to groups or deliberately generate a disparate impact on them.
Historical human biases are shaped by pervasive and often deeply embedded prejudices against certain groups, which can lead to their reproduction and amplification in computer models. In the COMPAS algorithm, if African-Americans are more likely to be arrested and incarcerated in the U.S. due to historical racism, disparities in policing practices, or other inequalities within the criminal justice system, these realities will be reflected in the training data and used to make suggestions about whether a defendant should be detained. If historical biases are factored into the model, it will make the same kinds of wrong judgments that people do.
Conversely, algorithms with too much data, or an over-representation, can skew the decision toward a particular result. Researchers at Georgetown Law School found that an estimated 117 million American adults are in facial recognition networks used by law enforcement, and that African-Americans were more likely to be singled out primarily because of their over-representation in mug-shot databases.22 Consequently, African-American faces had more opportunities to be falsely matched, which produced a biased effect.
Understanding the various causes of biases is the first step in the adoption of effective algorithmic hygiene. But, how can operators of algorithms assess whether their results are, indeed, biased? Even when flaws in the training data are corrected, the results may still be problematic because context matters during the bias detection phase.
In the former case, systemic bias against protected classes can lead to collective, disparate impacts, which may have a basis for legally cognizable harms, such as the denial of credit, online racial profiling, or massive surveillance.23 In the latter case, the outputs of the algorithm may produce unequal outcomes or unequal error rates for different groups, but they may not violate legal prohibitions if there was no intent to discriminate.
These problematic outcomes should lead to further discussion and awareness of how algorithms work in the handling of sensitive information, and the trade-offs around fairness and accuracy in the models.
It is not possible, in general, to have equal error rates between groups for all the different error rates.32 ProPublica focused on one error rate, while Northpointe honed in on another. Thus, some principles need to be established for which error rates should be equalized in which situations in order to be fair.
If the goal is to avoid reinforcing inequalities, what, then, should developers and operators of algorithms do to mitigate potential biases? We argue that developers of algorithms should first look for ways to reduce disparities between groups without sacrificing the overall performance of the model, especially whenever there appears to be a trade-off.
Yet, even with these governmental efforts, it is still surprisingly difficult to define and measure fairness.40 While it will not always be possible to satisfy all notions of fairness at the same time, companies and other operators of algorithms must be aware that there is no simple metric to measure fairness that a software engineer can apply, especially in the design of algorithms and the determination of the appropriate trade-offs between accuracy and fairness. Fairness is a human, not a mathematical, determination, grounded in shared ethical beliefs. Thus, algorithmic decisions that may have a serious consequence for people will require human involvement.
For example, while the training data discrepancies in the COMPAS algorithm can be corrected, human interpretation of fairness still matters. For that reason, while an algorithm such as COMPAS may be a useful tool, it cannot substitute for the decision-making that lies within the discretion of the human arbiter.41 We believe that subjecting the algorithm to rigorous testing can challenge the different definitions of fairness, a useful exercise among companies and other operators of algorithms.
We suggest that this question is one among many that the creators and operators of algorithms should consider in the design, execution, and evaluation of algorithms, which are described in the following mitigation proposals. Our first proposal addresses the updating of U.S. nondiscrimination laws to apply to the digital space.
Once the idea for an algorithm has been vetted against nondiscrimination laws, we suggest that operators of algorithms develop a bias impact statement, which we offer as a template of questions that can be flexibly applied to guide them through the design, implementation, and monitoring phases.
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