Being Hopeful about Algorithms

I’ve been attending “think-events” around algorithmic fairness of late, firstly in Philadelphia (courtesy of the folks at UPenn) and then in DC (courtesy of the National Academy of Science and the Royal Society).

At these events, one doesn’t see the kind of knee-jerk reaction to the idea of fairness in learning that I’ve documented before. But there’s a very thoughtful critique that comes from people who’ve spent a lot of time themselves thinking and working on these topics. And it goes something like this.

Do we expect more from algorithms than we expect from people? And is that reasonable?

I first heard this critique much earlier at  a Dagstuhl meeting on this topic, when I was asked this question by H. V. Jagadish (who has a great course on ethics in data mining). It came up indirectly during discussions at the Philadelphia event (about which I hope to say something later) and was phrased in this form by Vint Cerf at the Sackler Forum.

I found myself unable to answer it convincingly. We’ve had 1000s of years to set up institutions based on humans decision making. These processes have been flawed, anfdbiased. People have made decisions with implicit and explicit bias.

Why then do we demand then that algorithms do more? Why do we demand that they account for themselves and explain themselves in ways that we don’t ask human judges to do?

I used to have an answer. I argued that algorithms speak the language of mathematics and so we need to translate all our human ideals – of ethics, fairness and justice – into a form that an algorithm could understand. But then we start talking about accountability, interpretability, how an algorithm might explain itself, and what that might even mean.

Jon Kleinberg has this analogy of a learning algorithm as this incredibly obtuse friend that you bring to a party, that you have to explain EVERYTHING to. Where the food is, what the drinks are, what people are saying, and so on. We don’t have to do this for real people because they have a vast body of prior context to work with. Indeed, this prior context is what decides how they function in the world, and is made up of all kinds of heuristics and “biasing” of the space of possible outcomes (as Joanna Bryson puts it).

So it would seem that asking an algorithm for its “audit trail” is the equivalent of asking (say) a human judge “give me the entire story of your life experiences that explains why you made this decision”.

And of course we never do this. In fact, all we really do is set out a series of guidelines and expect the judges to be more or less consistent with them. Similarly for hiring, or credit decision, or any other kind of decision making. In other words, we expect a certain degree of procedural consistency while accepting that individuals may apply discretion based on their own perspective.

So I return to the question from before. Why do we expect an automated decision making process to be any better?

There’s an optimistic take on this. We can’t expect an audit trail from a human decision maker because we don’t have the capacity to generate one. That my verdict on a dog owner might in part be due to being bitten by a dog as a child is something that I’m unlikely to be able to cogently articulate. But it is at least a little unfair that I sentence dog owners more harshly for this reason.

But if we are able to produce such an audit trail from an algorithmic decision maker we do have the hope of revealing implicit preferences and biases based on the *algorithm’s* “life experiences” aka “training data”. And so we can expect more because we have the ability to do so.

An alternate perspective on this goes as follows. We’ve built up over the decades and centuries a system of checks and balances and accountability procedures for evaluating the quality of human decision making. We have laws that require non-discrimination, we have ways to remove decision-makers who make arbitrary decisions, and we have a social structure that makes decision-makers feel a sense of responsibility for their decisions.

None of these exist for algorithmic decision-making, or realistically can. We can’t call an algorithm to account for a bad decision: ultimately all liability rests on legal persons. So the next best thing is to make an algorithm assist in the decision making process, but require transparency so that the human decision-maker can’t blame the algorithm for bad decisions “It’s not me, it’s the algorithm!”, a story that played out in Cory Doctorow’s Human Readable.

There’s a tension between “let’s use automation wherever reasonable”, and “wait. how are you shifting harm?”. We don’t want to stop the deployment of algorithms in decision-making, and frankly I doubt that one could even if one wanted to. But it’s also not unreasonable to express some caution (and perhaps some humility) when doing this. We’re not expecting perfection from automated decision-making: it’s perfectly reasonable to expect just that we can do better than human decision makers. But why not expect that as well as expect a decision that we can understand? Why essentially give up by saying “the algorithm cannot both be powerful and understandable”. To me, that’s the real failure of hope.

Advertisements

Post-doc in Fairness at Data and Society

As part of the research we’re doing in algorithmic fairness we’re looking to hire a post-doctoral researcher who can help us bridge the gap between the more technical aspects of algorithmic fairness and the ways in which this discussion informs and is informed by the larger context in the social sciences. Specifically,

  • Candidates for this position should have a strong grasp of technical systems (including machine learning), as well as a rich understanding of socio-technical discussions. For example, candidates might have an undergraduate degree in computer science and a PhD in a social science field. Or they may have a more hybrid degree in an information school or CS program. They may be a data scientist or study data scientists.
  • Candidates should be able to translate between engineers and critics, feel comfortable at ACM/AAAI/IEEE conferences and want to publish in law reviews or social science journals as well as CS proceedings.
  • Candidates should be excited by the idea of working with researchers invested in fairness, accountability, and transparency in machine learning (e.g., fatml.org).
  • Preference given for researchers who have qualitative empirical skills.

If you might be such a person, please do send in an application (Role #1).

Data & Society is a wonderful place to be if you’re at all interested in this area. danah boyd has assembled a group of thinkers that represent the best kind of holistic thinking on a topic that intersects CS, sociology, political science and the law.

A funny thing happened on the way to the arXiv….

As I mentioned in the previous post, Sorelle Friedler, Carlos Scheidegger and I just posted a note to the arXiv on worldviews for thinking about fairness and nondiscrimination.

We uploaded the article last Friday, and it appeared on the arXiv on Sunday evening. By Monday late morning (less than 24 hours after the article was posted), we received this email:

I’m a reporter for Motherboard, VICE Media’s technology news site who frequently covers bias in machine learning. I read your paper posted to arXiv and would love to interview one of you for a piece on the work.

I assumed the reporter was referring to one of the two papers we’ve written so far on algorithmic fairness. But no, from the subject line it was clear that the reporter was referring to the article we had just posted! 

I was quite nervous about this: on the one hand it was flattering and rather shocking to get a query that quickly, and on the other hand this was an unreviewed preprint.

In any case, I did the interview. And the article is now out!

On the (im)possibility of fairness…

Ever since we started thinking about algorithmic fairness and the general issue of data-driven decision-making, there’s always been this nagging issue of “well what if there are cues in data that seem racist/sexist/(–)-ist and yet provide a good signal for a decision?”

There’s no shortage of people willing to point this out: see for example my post on the standard tropes that appear whenever someone discovers bias in some algorithmic process. Most of the responses betray a unexamined belief in the truth of what algorithms discover in data, and that is not satisfying either.

So the problem we’ve faced is this. If you examine closely the computer science literature on fairness and bias, it becomes clear that people are talking at cross-purposes: essentially arguing about why your orange is not more like my apple. And it has become clear that this is because of different assumptions about the world (how biased it is, how unbiased certain features are, and so on).

Here’s the pitch:

Can we separate out assumptions and beliefs about fairness from mechanisms that we deploy to ensure it? And in doing so, can we provide a useful vocabulary for talking about these issues within a common framework?

Here’s the result of our two-year long quest:

On the (im)possibility of fairness

What does it mean for an algorithm to be fair? Different papers use different notions of algorithmic fairness, and although these appear internally consistent, they also seem mutually incompatible. We present a mathematical setting in which the distinctions in previous papers can be made formal. In addition to characterizing the spaces of inputs (the “observed” space) and outputs (the “decision” space), we introduce the notion of a construct space: a space that captures unobservable, but meaningful variables for the prediction.
We show that in order to prove desirable properties of the entire decision-making process, different mechanisms for fairness require different assumptions about the nature of the mapping from construct space to decision space. The results in this paper imply that future treatments of algorithmic fairness should more explicitly state assumptions about the relationship between constructs and observations.

This paper has been a struggle to write. It’s a strange paper in that the main technical contribution is mainly conceptual: establishing what we think are the right basic primitives that can be used to express (mathematically) concepts like fairness, nondiscrimination, and structural bias.

We owe a great debt to our many friends in the social sciences community, as well as the decades of research on this topic in the social sciences. Much of the conceptual development we outline has been laid out in prose form by the many theories of social justice starting with Rawls, but particularly by Roemer. Our main goal has been to mathematize some of these ideas so that we can apply them to algorithms.

 

There’s a great deal of trepidation with which we release this: it’s in many ways a preliminary work that raises more questions than it answers. But we’ve benefited from lots of feedback within CS and without, and hope that this might clarify some of the discussions swirling around algorithmic fairness.

Testing algorithmic decision-making in court.

Well that was quick!

On the heels of the ProPublica article about bias in algorithmic decision-making in the criminal justice system, a lawsuit now before the Wisconsin Supreme Court could mark the first legal determination about the use of algorithmic methods in sentencing.

The first few paragraphs of the article summarize the issue at hand:

When Eric L. Loomis was sentenced for eluding the police in La Crosse, Wis., the judge told him he presented a “high risk” to the community and handed down a six-year prison term.

The judge said he had arrived at his sentencing decision in part because of Mr. Loomis’s rating on the Compas assessment, a secret algorithm used in the Wisconsin justice system to calculate the likelihood that someone will commit another crime.

Mr. Loomis has challenged the judge’s reliance on the Compas score, and the Wisconsin Supreme Court, which heard arguments on his appeal in April, could rule in the coming days or weeks. Mr. Loomis’s appeal centers on the criteria used by the Compas algorithm, which is proprietary and as a result is protected, and on the differences in its application for men and women.

Obama invokes Rawls

In a commencement speech at Howard University, Obama does an implicit shout out to Rawls and the Veil of Ignorance:

If you had to choose one moment in history in which you could be born and you did not know ahead of time who you were going to be , what nationality, or it gender, what race, whether you would be rich, poor, and a or straight — gay or straight, what faith you would be born into, you would not choose 100 years ago. you would not choose the 1950’s, the 1960’s, or the 1970’s. he would choose right now. If you had to choose a time to be in the world to be younger, gifted and black in america, you would choose right now

While I don’t necessarily agree with his conclusion, the fact that he invokes the Veil of Ignorance is what I find interesting.

See the clip here (starts at 12:45)

http://www.c-span.org/video/?409107-1/president-obama-delivers-commencement-address-howard-university&start=704

Frank Pasquale on Aeon

Algorithms are producing profiles of you. What do they say? You probably don’t have the right to know

Aeon has an extended piece by Black Box Society author Frank Pasquale where he describes not a future where algorithmic bias negatively impacts society, but a rather present where this already happens:

Job applicants at Walmart in the US and other large companies take mysterious ‘personality tests’, which process their responses in undisclosed ways. And white-collar workers face CV-sorting software that may understate, or entirely ignore, their qualifications.

The CEO of ZestFinance has proudly stated that ‘all data is credit data’ – that is, predictive analytics can take virtually any scrap of information about a person, analyse whether it corresponds to a characteristic of known-to-be-creditworthy people, and extrapolate accordingly. Such data might include sexual orientation or political views.