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Alex Chohlas-Wood Profile
Alex Chohlas-Wood

@LX_CW

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Asst professor at NYU interested in computational public policy and the justice system. Co-direct @comppolicylab. I'm at https://t.co/u9C7zzsmKP on Bsky

New York, NY
Joined June 2011
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@LX_CW
Alex Chohlas-Wood
6 months
NEW in Management Science!. My coauthors and I came up with a new consequentialist approach to designing equitable algorithms. Instead of imposing fairness criteria on an algorithm (like equal false negative rates), we aim for good outcomes. More in the đź§µ below! (1/)
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@LX_CW
Alex Chohlas-Wood
20 days
I’m excited to join @CouncilonCJ’s AI Task Force to think through ways that the responsible use of generative AI can advance fairness, transparency, and public safety in the criminal justice system!.
@CouncilonCJ
Council on Criminal Justice
21 days
AI presents significant opportunities and formidable challenges for criminal justice. Today, we (w/@RANDCorporation) are excited to announce a new Task Force on Artificial Intelligence to help guide the safe, ethical, & effective integration of AI in the criminal justice system.
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@LX_CW
Alex Chohlas-Wood
21 days
RT @CouncilonCJ: AI presents significant opportunities and formidable challenges for criminal justice. Today, we (w/@RANDCorporation) are e….
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@LX_CW
Alex Chohlas-Wood
5 months
Job alert!. We're hiring a clinical (teaching-based) Assistant Professor of Applied Statistics for Social Science Research at @NYU_ASH! . Application review begins on February 10, and the position would start on September 1. Apply here:
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@LX_CW
Alex Chohlas-Wood
6 months
@madisoncoots @itshenryzhu @EmmaBrunskill @5harad Ultimately, we’ll likely achieve better outcomes if we think of algorithms as *policies* — and design them in a way that aims for the specific policy goals we desire. (17/17).
@LX_CW
Alex Chohlas-Wood
6 months
NEW in Management Science!. My coauthors and I came up with a new consequentialist approach to designing equitable algorithms. Instead of imposing fairness criteria on an algorithm (like equal false negative rates), we aim for good outcomes. More in the đź§µ below! (1/)
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@LX_CW
Alex Chohlas-Wood
6 months
Learn more in our open-access paper, “Learning to be Fair: A Consequentialist Approach to Equitable Decision Making”, with @madisoncoots, @itshenryzhu, @EmmaBrunskill, and @5harad!. (16/).
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@LX_CW
Alex Chohlas-Wood
6 months
Many studies have framed fairness as a mathematical problem, proposing axioms without considering the consequences. In contrast, our approach:.- Focuses on outcomes.- Devises a computational framework for learning to be fair in an efficient and cost-effective manner.(15/).
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@LX_CW
Alex Chohlas-Wood
6 months
We use data from the Santa Clara County Public Defender to show that this approach would result in higher utility:.- During the learning phase AND.- After we stop learning!. Of course, this approach applies in any resource-constrained setting, not just for rides to court!.(14/)
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@LX_CW
Alex Chohlas-Wood
6 months
The framework we designed uses contextual bandits and optimization to:.- Learn how people respond to rides, and then provide rides to people who need them—even while we’re still learning.- Equitably allocate rides by modeling preferences as parameters in a convex objective.(13/).
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@LX_CW
Alex Chohlas-Wood
6 months
But randomized controlled trials are costly in a couple ways. First, people who would really benefit from a ride might be excluded if they’re randomized to a control arm. Second, we might waste money on rides for people who don’t need transportation assistance. (12/).
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@LX_CW
Alex Chohlas-Wood
6 months
How could we make decisions like this in the real world?. One approach would be to run a randomized controlled trial to learn how people respond to rides. We could then estimate the tradeoffs at hand, and choose an tradeoff that best reflects our preferences. (11/)
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@LX_CW
Alex Chohlas-Wood
6 months
This suggests that there’s no one-size-fits-all definition of fairness. Instead, we should make decisions in a way that reflects our preference for how to make difficult tradeoffs. (In practice, one could run a survey like the above to elicit preferences from people.).(10/)
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@LX_CW
Alex Chohlas-Wood
6 months
To illustrate, we asked 300 Americans how they would make this tradeoff. After explaining the problem, we let them choose their preferred outcome. Most people preferred an outcome other than demographic parity—even people in the same political party!.(9/)
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@LX_CW
Alex Chohlas-Wood
6 months
Fortunately, we don’t have to follow only one of these approaches. We could instead balance between these approaches in a way that feels most fair. But “what feels fair” is ultimately a matter of personal preference, and depends on the exact tradeoff in question. (8/)
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@LX_CW
Alex Chohlas-Wood
6 months
This would reduce disparities in who gets a ride. But there would be real drawbacks!.- We’d pay for longer rides to court, so.- We’d provide fewer rides overall, so.- More people would go to jail for missing court. In other words, there’s an inherent tradeoff at play. (7/)
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@LX_CW
Alex Chohlas-Wood
6 months
It might seem wrong to exclude most Black and Hispanic residents like this. So what should we do?. We could instead provide a ride to an equal share of court attendees from every neighborhood. (For researchers in ML fairness, this is akin to imposing demographic parity.).(6/).
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@LX_CW
Alex Chohlas-Wood
6 months
But there’s a catch! Take Boston as an example. In prioritizing cheap + short rides, imagine that we drew from people who lived close to the courthouse (like in the map). By trying to be efficient with our budget, we’d exclude many Black + Hispanic residents of Boston. (5/)
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@LX_CW
Alex Chohlas-Wood
6 months
So we’d have to choose who gets a ride. A natural way to do this would be to select people who:.a) Wouldn’t attend normally, but would attend if provided a ride.b) Live close to court, so the ride is cheap. This would maximize court appearances given our budget. Seems good!.(4/).
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@LX_CW
Alex Chohlas-Wood
6 months
What if we wanted to improve court attendance rates even more?. One possible initiative would be providing people with free rides to court. But with a limited budget, we wouldn’t have enough funding to give everyone a ride. (3/)
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@LX_CW
Alex Chohlas-Wood
6 months
Imagine a government initiative that aims to improve court attendance rates. In other research, we’ve already shown that sending automated court date reminders can increase court appearance rates and reduce pretrial incarceration. (2/).
@LX_CW
Alex Chohlas-Wood
2 years
In a new randomized experiment at the Santa Clara County Public Defender Office, my colleagues and I found that text message reminders reduce *incarceration* for missed court dates by over 20%! More in the đź§µ below.
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