A New Study about Gender and Pay Gaps

I learned about this via Marginal Revolutions and Freakonomics. Briefly, Uber keeps an enormous amount of data on its drivers, allowing economists to study the different ways that women and men are paid. The Freakonomics folks interviewed an Uber economist:

LIST: So we have mounds and mounds of data. We have millions of drivers. We have millions of observations, and 25 million driver-weeks across 196 cities. So just the depth of the data and the understanding of both the compensation function and the production function of drivers gives us a chance to — once we observe if there is indeed a gap — gives us a chance to unpack what are the features that can explain that gap.

They did find a pay gap that broke down by gender — 7%:

LIST: We found something very surprising. What you find is that men make about 7 percent more per hour on average …

DIAMOND: … which is pretty substantial.

LIST: For doing the exact same job in a setting where work assignments are made by a gender-blind algorithm and pay structure’s tied directly to output and not negotiated.

Was it because of discrimination on an individual level? They don’t think so:

DUBNER: Right. So let me just make sure I’m clear. You’re saying there’s no discrimination on the Uber side, on the supply side, because the algorithm is gender-blind and the price is the price. And you’re saying there’s no discrimination on the passenger side. So does that mean that discrimination accounts for zero percent of whatever pay gap you find or don’t find between male and female Uber drivers?

LIST: That’s correct.

The interview is long and full of juicy details and tough questions. I haven’t read the whole thing carefully yet, but it’s fascinating all the way through:

DUBNER: What is the overall driver attrition rate? I don’t know whether it’s measured in six months or a year, or whatever.

DIAMOND: Yes, six months is what we’ve been looking at.

LIST: More than 60 percent of those who start driving are no longer active on the platform six months later.

DIAMOND: So the six-month attrition rate for the whole U.S. for men is about 63 percent, and for women it’s about 76 percent.

DUBNER: Wow. So that would connote to me, an amateur at least, that maybe this gender pay gap among Uber drivers is reflected in the fact that women leave it so much more. Maybe it’s just a job that on average, women really don’t like. Is that measurable?

There’s a whole discussion about that, and a lot  of other things too besides.

So what does explain the 7% pay gap, in the end? They have theories, foremost among them is that men drive faster than women:

LIST: That’s right. So after we account for experience now we’re left scratching our heads. So, we’re thinking, “Well, we’ve tried discrimination. We’ve done where, when. We’ve done experience. What possibly could it be?” What we notice in the data is that men are actually completing more trips per hour than women. So this is sort of a eureka moment.

DUBNER: They’re driving faster, aren’t they?

HALL: Yeah. So the third factor, which explains the remaining 50 percent of the gap, is speed.

It’s not hard to speculate about how something like how quickly men vs. women tend to drive to possible sources of systemic cultural discrimination. (Are men more confident drivers? Are they less fearful of the law? etc.)

Still, what these economists are finding is that (a) the pay gap is persistent, even in the face of an equalizing pay structure and (b) possible factors explaining the gap will not be simple to address. For example, one source of the gap could be that men tend to work more hours, gaining more experience which pays dividends later, so that one source of the Uber gap is that men are getting paid for experience, not something that you can easily address:

DIAMOND: I think this is showing that the gender pay gap is not likely to go away completely anytime soon. Unless somehow, things in our broader society really change, about how men and women are making choices about their broader lives, than just the labor market. But it’s not also a worry that the labor market is not functioning correctly. It makes sense to compensate people who are doing more productive work. It makes sense to pay people more if they work more hours. I mean, I don’t think those are things that we would ever consider thinking should be changed because that they’re a problem. Those are just real reasons that productivity can differ between men and women. And we should compensate people based on productivity.

What would the implications of this finding be? It’s not that individual discrimination isn’t responsible for the pay gap in general — this would likely depend on the field and the job, right? — but that there are deeper factors at play that might explain a pay gap between men and women.

This shouldn’t really surprise anyone working in education. Men and women teachers are paid according to the same standardized salary schedule in public schools. If you pooled all the male and female teachers, though, you’d see that there is a gender pay gap because of disproportionate numbers of male/female teachers in elementary vs. middle vs. high school. Men make more not because administrators choose to pay them more — largely, it’s because men choose to teach older kids more than women.

There’s no easy way to address this discrimination, if it’s even quite right to call this discrimination. Certainly it’s possible (likely? I don’t really know) that cultural factors partly explain the choices of men and women. At a certain level, though, this is irrelevant. Do we want to mess with the choices of men and women about where and how to work?

(This quickly gets tangled in questions of diversity and representation. Is it a policy priority to ensure that men and women are represented in the teaching force at numbers that are proportional to the students they instruct?)

There might be structural pay gaps that outstrip what can be explained by discrimination. Whether biological or culturally constructed, there might be persistent and not-bad differences between men and women. As I continue to think about this, it seems to make sense to me that we’d want to continue to battle discrimination while also thinking of ways to address inequities using other angles, besides battling pay gaps. Past a certain point, of course.

One last juicy morsel, at the very end of the interview. As Uber introduces tipping it seems that drivers make LESS and that the pay gap narrows somewhat because women are tipped more:

LIST: Yeah, I think when you look at the tipping data in general, you do find a tilt in favor of women compared to men in general. We’ll have a tipping paper for you in a few months. Because the economics of tipping is sort of wide open, and we’ll have a paper just like this one called something like “A Nationwide Experiment on Tipping.”

DUBNER: Right.

LIST: And we’ll do the tipping roll out and show you how earnings change with the introduction of tipping. And the earnings actually go down a little bit. They don’t go up after you introduce tipping.

DUBNER: Now how can that be?

LIST: What happens is the supply curve shifts out enough to compensate the higher tips. And when the supply curve shifts out, the organic wages go down. And what you have is drivers are underutilized. So what I mean by that is typically they’ll sit in their car empty 35 percent of the time. With tipping, maybe it’ll go up to 38 percent of the time.

DUBNER: In other words, the wage declines because more drivers think they’re going to make more money since tips are now included, but that increases the supply of drivers, which means there’s less demand to go around.

LIST: Exactly. That’s perfect.

 

Reading “A Root Cause of the Teacher-Diversity Problem”

Check it out here, it’s great.

So far the main effect of having a second kid in the house has been to make me, in pretty much every way, a little bit dumber. You know what I mean by dumber: not as clever, etc.

Anyway, one of the ways in which I’m dumber is that I’m a worse reader with worse impulse control. So last night I found myself reading an article right before bed (another mistake) and having trouble understanding a perfectly clear article by Melinda D. Anderson (the one I mentioned). And then I had the questionable decision to tweet the author my questions.

I really feel for journalists on Twitter. How do you know when to engage, when someone is worth talking to? Melinda was very generous in helping me understand what she wrote, as was Grace Chen, so I figured I’d write a bit explaining what I understood, out of thanks.

***

About 15% of public school students are Black:

Screenshot 2018-01-25 at 8.23.56 PM.png

About 16% of public school students were Black in 2012, but only 7% of teachers were Black.

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(Figures and sources from this NCES report.)

So even as Black people make up about 12% of the general population in the US and even as that share of the population is modestly rising, the percentage of Black teachers is not increasing. A disproportionate percentage of the teaching population is not Black.

The question is, why? There are roughly two sorts of answers.

Supply-side: The issue is in the pipeline. This is mostly what people talk about, and it takes myriad forms: Black people graduate high school and college at lower rates, and hence are less available for teaching positions. Black people are disproportionately uninterested in becoming teachers, for whatever reasons.

Indeed, that NCES report that I linked to focuses on the pipeline:

Screenshot 2018-01-25 at 8.46.32 PM.png

But there’s another set of factors to look at: what if the teachers are there, but schools just won’t hire Black teachers?

Demand-side: Districts are biased, either implicitly or explicitly, against Black teachers. For reasons rooted in stereotype or false-associations, Black candidates are less appealing to schools, so they don’t get hired.

That’s what Melinda wrote about in the Atlantic piece. She wrote about districts that were sued for being biased against Black teachers, and the court agreed. (Or, rather, one district was issued a decision by a court to stop discriminating against Black teachers, and another took action after they got spooked by a suit that was in the works.)

One thing I was wondering is whether it’s really possible to disentangle supply and demand considerations. If Black teachers experience bias in school hirings then they’ll be less likely to pursue careers in schooling. If you start with a dearth of Black teachers in the pipeline, biases will creep up. These factors might not be possible to truly separate.

My own school has disproportionately few non-White teachers (and students). Is the issue supply-side or demand-side? Both, probably, though I suppose it only matters to the extent that this helps a school decide what to do. As Grace points out, most in education prefer to frame this as a “won’t somebody think about the children” issue, i.e. it helps kids to have Black teachers. I’m not saying I’m skeptical of that, but as Grace notes this could be a way for schools to avoid responsibility for bias — the dearth of Black teachers is then not unlike having not enough computers or too few pencils.

But how do you tell a school to stop being biased against Black job candidates? The answer for both of these schools was affirmative-action policies. Is there a stronger case for affirmative action in the presence of bias than if the problem is in the pipeline? I think so, though I feel fuzzy about how to think about this.

Many people I talk to who are otherwise strong advocates for diversity in the teaching force are uncomfortable with affirmative action. But maybe there’s an important difference to folks between affirmative action to correct a present bias vs. affirmative action to address a historical bias?

I’m confused. Melinda said at one point in our Twitter chat that she wrote the piece to provoke thinking and discussion, and it’s definitely done that for me.

Chimps are better than humans at some working memory tasks

Amazing. From the research report:

Chimpanzee memory has been extensively studied. The general assumption is that, as with many other cognitive functions, it is inferior to that of humans; some data, however, suggest that, in some circumstances, chimpanzee memory may indeed be superior to human memory. Here we report that young chimpanzees have an extraordinary working memory capability for numerical recollection — better even than that of human adults tested in the same apparatus following the same procedure

Watch that video for details of the test. The biologists think this might be connected to eidetic imagery:

These data showed that the chimpanzee subjects can memorize at a glance the Arabic numerals scattered on the touch screen monitor and Ayumu outperformed all of the human subjects both in speed and accuracy. Our results may be reminiscent of the phenomenon known as ‘eidetic imagery’ found by Jaensch. Eidetic imagery has been defined as the memory capability to retain an accurate, detailed image of a complex scene or pattern. It is known to be present in a relatively high percentage of normal children, and then the ability declines with age…The results fit well with what we know about the eidetic imagery in humans.

To me, this raises the tantalizing possibility that our working memory limitations are a core part of what it means to be human. We’ve been designed to hold fewer things in our head at once.

Other things I want to read, in relation to all this. I’ll add more if I find (or if people find for me!) other related reads.

Evolution of working memory

Does this connect to dual process theories? Dual process theories of higher cognition

Gutierrez on the tensions of teaching

Although teachers must recognize they are teaching more than just mathematics, they also have to reconcile that fact with the idea that, ultimately,  they are responsible for helping students learn mathematics. Teachers who are committed to equity cannot concern themselves with their students’ self-esteem and negotiated identities to the exclusion of the mathematics that the students will be held responsible for in later years. Yet preparation for the next level of mathematics must also not be the overriding feature of a teacher’s practice. In answer to which of the two foci are important (teaching students or teaching mathematics), I would answer “neither and both.” It is in embracing the tension…”

Rochelle Gutierrez, Embracing the Inherent Tensions in Teaching Mathematics from an Equity Stance

What does it mean to live in tension? I suppose it’s an emotional feeling, of not knowing at any given moment which way you should lean. I like the idea that teaching involves tensions that can’t be resolved, though I admit I’m still fuzzy on what it means to teach in a way that reflects such a tension.