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Algorithmic bias is a term used to describe situations where an algorithm systematically produces outcomes that are less favorable to individuals within a particular group, despite there being no relevant properties of individuals in that group that should lead to distinct outcomes from other groups . As “big data” approaches become increasingly popular for optimizing complex tasks, numerous examples of algorithmic bias have been identified, and sometimes the implications can be serious. As a result, algorithmic bias has become a matter of concern, and there are ongoing efforts to develop methods for detecting it and mitigating its effects. However, despite increasing recognition of the problems due to algorithmic bias, sometimes bias is embraced by the individuals it benefits. For example, in her book Weapons of Math Destruction, Cathy O’Neil discusses the gaming of algorithmic ranking of universities via exploitation of algorithmic bias in ranking algorithms. While there is almost universal agreement that algorithmic rankings of universities are problematic, many faculty at universities that do achieve a top ranking choose to ignore the problems so that they can boast of  their achievement.

Google Scholar coauthor lists are useful. I occasionally click on the coauthor lists to find related work, or to explore the collaboration network of a field that may be tangentially related to mine but that I’m not very familiar with. At some point I started noticing that the lists were almost entirely male. Frequently, they were entirely male. I decided to perform a simple exercise to understand the severity of what appeared to me to be a glaring problem:

Let the Google Scholar coauthor graph be a directed graph GS = (V,E) whose vertices correspond to authors in Google Scholar, and with an edge $(v_1,v_2) \in E$  from $v_1 \in V$ to $v_2 \in V$ if author $v_2$ is listed as a coauthor on the main page of author $v_1$. We define an author to be manlocked (terminology thanks to Páll Melsted) if its out-degree is at least 1, and if every vertex that it is adjacent to (i.e., for which (v,w) is an edge) and that is ranked among the top twenty coauthors by Google Scholar (i.e., w appears on the front page of v), is a male.

For example, the Google Scholar page of Steven Salzberg is not manlocked: of the 20 coauthors listed on the Scholar page, only 18 are men. However several of the vertices it is adjacent to, for example the one corresponding Google Scholar page of Ben Langmead, are manlocked. There are so many manlocked vertices that it is not difficult, starting at a manlocked vertex, to embark on a long manlocked walk in the GS graph, hopping from one manlocked vertex to another. For example, starting with the manlocked Dean of the College of Computer, Mathematical and Natural Sciences at the University of Maryland, we find a manlocked walk of length 14 (I leave it as an exercise for the reader to find the longest walk that this walk is contained in):

A country is doubly landlocked when it is surrounded only by landlocked countries. There are only two such countries in the world: Uzbekistan and Lichtenstein. Motivated by this observation, we define a vertex in the Google Scholar coauthor graph to be doubly manlocked if it is adjacent only to manlocked vertices.

Open problem: determine the number of  doubly manlocked individuals in the Google Scholar coauthor graph.

Why are there so many manlocked vertices in the Google Scholar coauthorship graph? Some hypotheses:

1. Publications by women are cited less than those of men (Aksnes et al. 2011).
2. Men tend to publish more with other men and there are many more men publishing than women (see, e.g. Salerno et al. 2019, Wang et al. 2019).
3. Men who are “equally contributing” co-first authors are more “equal” than their women co-first authors (Broderick and Casadevall 2019). Google Scholar’s coauthor recommendations may give preference to first co-first authors.
4. I am not privy to Google’s algorithms, but Google Scholar’s coauthor recommendations may also be biased towards coauthors on highly cited papers. Such papers will be older papers. While today the gender ratio today is heavily skewed towards men, it was even more so in the past. For example, Steven Salzberg, who is a senior scientists mentioned above and lists 18 men coauthors out of twenty on his Google Scholar page, has graduated 12 successful Ph.D. students in the past, 11 of whom are men. In other words, the extent of manlocked vertices may be the result of algorithmic bias that is inadvertently highlighting the gender homogeneity of the past.
5. Many successful and prolific women may not be using Google Scholar (I can think of many in my own field, but was not able to find a study confirming this empirical observation). If this is true, the absence of women on Google Scholar would directly inflate the number of manlocked vertices. Moreover, in surveying many Google Scholar pages, I found that women with Google Scholar pages tend to have more women as coauthors than the men do.
6. Even though Google Scholar allows for manually adding coauthors, it seems most users are blindly accepting the recommendations without thinking carefully about what coauthorship representation best reflects their actual professional relationships and impactful work. Thus, individuals may be supporting the algorithmic bias of Google Scholar by depending on its automation. Google may be observing that users tend to click on coauthors that are men at a high rate (since those are the ones being displayed) thus reinforcing for itself with data the choices of the coauthorship algorithm.

The last point above (#4) raises an interesting general issue with Google Scholar. While Google Scholar appears to be fully automated, and indeed, in addition to suggesting coauthors automatically the service will also automatically add publications, the Google Scholar page of an individual is completely customizable. In addition to the coauthors being customizable, the papers that appear on a page can be manually added or deleted, and in fact even the authors or titles of individual papers can be changed. In other words, Google Scholar can be easily manipulated with authors using “algorithmic bias” as a cover (“oops, I’m so sorry, the site just added my paper accidentally”). Are scientists actually doing this? You bet they are (I leave it as an exercise for the reader to find examples).

Yesterday I found out via a comment on this blog that Yuval Peres, a person who has been accused by numerous students, trainees, and colleagues of sexual harassment, will be delivering a lecture today in the UC Davis Mathematical Physics and Probability Seminar.

The facts

I am aware of at least 11 allegations by women of sexual harassment by Yuval Peres (trigger warning: descriptions of sexual harassment and sexual assault):

1. Allegation of sexual harassment of a Ph.D. student in 2007. Sourcedescription of the harassment by the victim.
2. Allegation of sexual harassment by a colleague that happened when she was younger. Source: description of the harassment by the victim.
3. Allegation of sexual harassment of a woman prior to 2007. Source: report on sexual harassment allegations against Yuval Peres by the University of Washington (received via a Freedom of Information Act Request).
4. Allegation of sexual harassment by one of Yuval Peres’ Ph.D. students several years ago. Source: report on sexual harassment allegations against Yuval Peres by the University of Washington (received via a Freedom of Information Act Request).
5. Allegation of sexual harassment of a colleague. Source: personal communication to me by the victim (who wishes to remain anonymous) via email after I wrote a post about Yuval Peres.
6. Allegation of sexual harassment of a graduate student. Source: personal communication to me by the victim (the former graduate student who wishes to remain anonymous) via email after I wrote a post about Yuval Peres.
7. Recent allegations of sexual harassment by 5 junior female scientists who reported unwanted advances by Yuval Peres to persons that leading figures in the CS community describe as “people we trust without a shred of doubt”. Source: a letter circulated by Irit Dinur, Ehud Friedgut and Oded Goldreich.

The details offered by these women of the sexual harassment they experienced are horrific and corroborate each other. His former Ph.D. student (#4 above) describes, in a harrowing letter included in the University of Washington Freedom of Information Act (FOIA) disclosed report, sexual harassment she experienced over the course of two years, and many of the details are similar to what is described by another victim here. The letter describes sexual harassment that had its origins when the student was an undergraduate (adding insult to injury the University of Washington did not redact her name with the FOIA disclosed report). I had extreme difficulty reading some of the descriptions, and believe the identity of the victim should be kept private despite the University of Washington FOIA report, but am including one excerpt here so that it’s clear what exactly these allegations entail (the letter is 4.5 pages long):

Trigger warning: description of sexual harassment and sexual assault

“While walking down a street he took my hand, I took it away with pressure but he grabbed it by force. I was pretty afraid of getting in a fight with my PhD advisor. He stroked my hand with his fingers. I said stop, but he ignored it. I started talking about math intending to make the situation less intimate. But he used me being distracted and put his arms around my waist touching my bud. I was in shock. We came by a bench. He asked me to sit down. I removed his hands and sat down far from him. He came closer and told me that I had a body like a barbie doll. I changed topic again to math, but he took my hand and kissed the back of my hand. I freed my hand with a sudden move, and saw him leaning towards me touching my hair and trying to kiss me. I felt danger and wanted to go home. Yuval was again holding my hand, but this time there was no resistance from me. I thought if I let him hold my hand it is less likely that he harms me. Arriving at my home he tried to give me a kiss. I was relieved when he drove away.”

The victim sent this letter to the chairs of the mathematics and computer science departments at the University of Washington and made a request:

“I am not the only female who was sexually harassed by Yuval Peres and I am convinced that I was not the last one. Therefore, I hope with this report that you take actions to prevent incidents like this from happening again.”

Instead of passing on the complaint to Title IX, and contrary to claims by some of Yuval Peres’ colleagues that appear in the University of Washington FOIA disclosure report that the case was investigated, the chairs of the University of Washington math and computer science departments (in a jointly signed letter) offered Yuval Peres a path to avoiding investigation:

“As you know from our e-mail to you [last week], your resignation as well as an agreement not to seek or accept another position at the University will eliminate the need for the University to investigate the allegations against you.”

Indeed, Yuval Peres resigned within two months of the complaint with no investigation ever taking place. This is the email the victim received afterwards from the chair of the mathematics department, in response to her request that “I hope with this report that you take actions to prevent incidents like this from happening again”:

“I believe this resolution [Yuval Peres’ resignation] has promptly and effectively addressed your concerns.”

At least 8 women have since claimed that they were sexually harassed.

Seminar and a dinner

As is customary with invited speakers, the organizer of the seminar today wrote to colleagues and student in the math department at UC Davis on Monday letting people know that “there will be a dinner afterward, so please let me know if you are interested in attending.”

Here is a description of a dinner Yuval Peres took his Ph.D. student to, and a summary of the events that led to him and his Ph.D. student walking down the street when he forcibly grabbed her hand:

Trigger warning: description of sexual harassment and sexual assault

“I tried to keep the dinner short, but suddenly he seemed to have a lot of time. He paid in cash in contrast to dinners with other students, and offered to take me home. In his car half way to my place he said he would only take me home if I show him my room (I was living in a shared apartment with other people). I thought it was a joke and said no. He laughed and grabbed my hand. Arriving at home I said goodbye. But when I got out of the car he said that I promised to show him my room. I said that I did not. However, he followed me to the backdoor of the house. Fortunately some of my roommates were at home. It bothered Yuval that we were not alone at my home, so he said we should take a walk outside. I felt uncomfortable but I still needed to talk about my PhD thesis work. While walking down the street he took my hand, I took it away with pressure but he grabbed it with force…”

I wonder how many graduate students at UC Davis will feel comfortable signing up for dinner with Yuval Peres tonight, or even be able to handle attending his seminar after reading of all the sexual harassment allegations against him?

The challenge is particularly acute for women. I know this from comments in the reports of sexual harassment that I’ve read, from the University of Washington FOIA disclosed report, and from personal communication with multiple women who have worked with him or had to deal with him. Isn’t holding seminars (which are an educational program) that women are afraid to attend, and are therefore de facto excluded from and being denied benefit of, in a department that depends heavily on federal funding, a Title IX violation? Title IX federal law states that

“No person in the United States shall, on the basis of sex, be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any education program or activity receiving Federal financial assistance.”

An opinion

It’s outrageous that UC Davis’ math department is hosting Yuval Peres for a seminar and dinner today.

[Update November 10th, 2019: after reading this post a former Ph.D. student at UC Berkeley wrote that “Another PhD student in Berkeley probability and I both experienced this as well. About time this is called out so no more new students are harassed.“]

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