Do risk preferences account for 1.4 percentage points of the gender pay gap?

A few days ago, this study of gender pay differences for Uber drivers came out. The key finding, that women earned 7% less than men, was stunning because Uber uses a gender-blind algorithm. The figure below was the most interesting one from the study as it summarized the differences in pay quite well.


To explain this, the authors highlight a few explanations borne out by the data: men drive faster allowing them to have more clients; men have spent more time working for Uber and have more experience that may be unobserved; choices of where and when to drive matters. It is this latter point that I find fascinating because it speaks to an issue that I keep underlining regarding pay gaps when I teach.

For reasons that may be sociological or biological (I am agnostic on that), men tend to occupy jobs that have high rates of occupational mortality (see notably this British study on the topic) in the forms of accidents (think construction, firemen) or diseases (think miners and trashmen). They also tend to take the jobs in further removed areas in order to gain access to a distance premium (which is a form of risk in the sense that it affects  family life etc.). The premiums to taking risky jobs are well documented (see notably the work of Kip Viscusi who measured the wage premium accruing to workers who were employed in bars where smoking was permitted). If these premiums are non-negligible but tend to be preferred by men (who are willing to incur the risk to be injured or fall sick), then risk preferences matter to the gender wage gap.

However, there are hard to properly measure in order to assess the share of the wage gap truly explained by discrimination. Here with the case of Uber, we can get an idea of the amplitude of the differences. Male Uber drivers prefer riskier hours (more risks of having an inebriated and potentially aggressive client), riskier places (high traffic with more risks of accidents) and riskier behavior (driving faster to get more clients per hour).  The return to taking these risks is greater earnings. According to the study, 20% of the gap stems from this series of choices or roughly 1.4 percentage points.

I think that this is significantly large to warrant further consideration in the future in the debate. More often than not, the emphasis is on education, experience, marital status, and industry codes (NAICS code) to explain wage differences. The use of industry codes has never convinced me. There is wide variance within industries regarding work accidents and diseases. The NAICS codes industries by wide sectors and then by sub-sectors of activities (see for example the six-digits codes to agriculture, forestry, fishing and hunting here). This does not allow to take account of the risks associated with a job. There are a few study that try to account for this problem, but there are … well … few in numbers. And rarely are they considered in public discussions.

Here, the Uber case shows the necessity to bring back this subtopic in order to properly explain the wage gap.


Lunchtime Links

  1. Interview with a secessionist
  2. Ducking questions about capitalism
  3. The perverse seductiveness of Fernando Pessoa
  4. Yet in this simple task, a doffer in the USA doffed 6 times as much per hour as an adult Indian doffer.”
  5. Conflicted thoughts on women in medicine
  6. The Devil You Know vs The Market For Lemons (car problems)

Is persecution the purpose?


Last week, Rebecca Tuvel, an Assistant Professor of Philosophy, had her recent article in Hypatia, ‘In Defence of Transracialism’, denounced in an open letter signed by several professional scholars (among others). They accused her of harming the transgender community by comparing them with the currently more marginalized identity of transracialism. William Rein, on this blog, and Jason Brennan at Bleeding Heart Libertarians, have written valuable defences of Tuvel’s right to conduct academic research in this area even if some find it offensive.

Events have moved fast. The associate editors initially seemed to cave in to pressure and denounced the article they had only just published. The main editor, Sally Scholz, has since disagreed with the associate editors. Critically, Tuvel’s colleagues at Rhodes College have given her their support so it looks like the line for academic freedom might be holding in this case. Without wishing to engage too much in the hermeneutics of suspicion, I think there are grounds to doubt the depth of the critics’ attitudes. I base this on my reading of Judith Butler, who is one of the signatories to the open letter arguing for Tuvel’s article to be retracted.

Seven years ago, I managed to read Judith Butler’s Gender Trouble. Although there are many variations in the movement, Butler is a central figure in the post-structuralist , non-gender-essentialist, feminism that inspires much of the contemporary ‘social justice’ movement. When I got past Butler’s famously difficult prose, I found a great deal of ideas I agreed with. I wrote up a brief piece comparing Butler’s concerns with violently enforced gender conformity to classical liberal approaches to personal autonomy. I also identified some problems.

First, Butler’s critique of the natural sciences seems to completely miss the mark. Butler associates gender essentialism with the study of genetics, when, in fact, genetics has done more than almost anything else to explore the contingency and variation of biological sexual expression in nature. The same applies to race and ethnicity.

Second, more importantly, Butler insists that there is no underlying authentic gender or sexual identity. All identities are ultimately constituted by power relations and juridical discourses. You find this argument repeated among social justice proponents who insist all forms of identity are products of ‘social construction’ rather than ever being based on natural facts. As a result, all personal identity claims are only ever historical and strategic. They are attempts to disrupt power relations in order to liberate and empower the subaltern and oppressed albeit temporarily

I don’t think this is perfectly factually true but lets accept it for now as roughly true. This means that transracialism itself might become, or could already be, another example of the strategic disruption of contemporary juridical discourses, this time about race and ethnicity. The same people currently denouncing Tuvel could very easily insist on the acknowledgement of transracial identity in five or ten years time, and denounce those who hold their current views. From their own position, which explicitly rejects any ultimate restrictions on identity formation, we have no warrant to know otherwise.

In this sense, Tuvel might not be ‘wrong’ at all, just slightly ahead of the social justice curve. And her critics wouldn’t actually be changing their minds, just changing their strategies. Meanwhile, people who actually take their identities seriously should be wary of their academic ‘allies’. They can quickly re-orientate their attitude such that a previously oppressed identity comes to be re-configured as an oppressive and exclusionary construct.

If all claims in this area are strategic, rather than factual, as Butler claims, then why try to damage a philosopher’s career over it? Why provoke an academic journal almost to self-destruct? Rather than working out which ideas to denounce, we should critique the strategy of denouncement (or calling out) itself. In that vein, much as I disagree wholly with the stance of its editorial board, I think calling into question Hypatia’s status as an academic journal, is premature.

Race as a bundle and its implications

As I mentioned in my last post, I have been given the topic of race increased thought recently.

One of the recent developments in political science has been thinking of race not as a dichotomous variable, but as a bundle of related but distinct characteristics. Race is not simply phenotype, but a mixture of such things as one’s dialect, diet, and socioeconomic status among other things.


The idea to me seems obvious, which makes me inclined to believe it. The thing is, if we take this broader approach to what race is, what are the implications for prior work not only in regards to race but the effect of demographic characteristics generally.

Race is already difficult to conduct research in because it is assigned at birth which makes it difficult to manipulate and which influences other characteristics we would ordinarily ‘control’ for in statistical analysis. To my knowledge there isn’t a ‘race ray’ that we can use to randomly assign being ‘black’ in an experiment. Tracing causality is possible, but difficult enough even in ideal situations.

Take for example the gender wage gap argument. When you control for education, presence of children, and other characteristics the gap in wages between males and females vanishes. However many of these characteristics are impacted by one’s gender. While females are not discriminated against ceteris paribus, being female does increase one’s likelihood of having to be the primary care taker for children and has historically decreased educational outcomes. In this broader sense there is a gender wage gap.

What can be done about it though? Men can try to share more of the house duties with their wives, but my general observation in life has been that children prefer being cared for by their mothers over their fathers. Should we try to do something about it? Are there advantages to one member of the household specializing in housework?

Or, if you prefer to think of the question purely in regards to race let us consider crime rates by race. I am not convinced that blacks have any higher propensity to crime than whites. However blacks are more likely to grow up in poverty and have lower educational outcomes than other races, which in turn leads to higher crime rates statistically speaking. Where should the arrow of causality be pointed towards: race, education, socioeconomic status?

Race is a difficult concept to think about. However it is precisely the difficulty with discussing it which begs that it be thought about more. I believe we liberals have a particular duty to think about race more because if we don’t then our ideological rivals will continue to dominate the conversation.

See here for an un-gated draft of the relevant paper: Sen, Maya, and Omar Wasow. “Race as a Bundle of Sticks: Designs that Estimate Effects of Seemingly Immutable Characteristics.” Annual Review of Political Science 19 (2016): 499-522.

To Women Voters:

I take the liberty to point out a small number of issues that I am told are important to women. I do it because I used to be a respectable social scientist and because I have been retired for ten years which gives me plenty of time to stay informed.

Women voters have been misled for years by propaganda explicitly pointed at them. It wasn’t necessarily a conspiracy though but a kind of uncritical cultural convergence. Many of those who spread misinformation believe it themselves. So, in a way, they are morally innocent. That’s no reason to follow them down the wrong path, and down the cliff. Below are five topics about which you may have received false information that has been repeated over and over until it sounded true.

The first female president

There is a widespread feeling among American women that it’s time finally to elect a female president. For some, it’s a sort of symbolic restitution. I can’t speak to this because I am only a man. Other voters, both females and males, seem to think that a female presidency would result in significant improvements in the lives of American women. A relevant reminder: Eight years ago, Americans elected the first African-American president. For many, it was a vote filled with hope for positive change in the area of race. After two Obama administrations, almost eight years later, it’s time to take stock. However you evaluate the Obama administrations in general, two facts stand out. First, race relations in American have not improved (to say the least). Second, African-Americans are not better off than they were eight years ago. In fact, they are slightly worse off economically. (My own position on having a woman President is straightforward: I would vote for Stanford Professor Condoleeza Rice, for President, in a heartbeat.)


The 1973 Roe vs Wade decision made abortion on demand available throughout the territory of the United States. Candidate Trump has provided a list of potential nominees to the Supreme Court . Some of those nominees are pro-life. This raises the question of what would happen in the unlikely event that Roe vs Wade were overturned by a new Supreme Court. You may have been led to believe that abortion would become illegal. That’s simply not true. Legislation on abortion – if any – would revert to the individual states as the Constitution requires (same as murder, theft, sequestration, and spitting on the sidewalk). The likelihood that all fifty states would forbid abortion on demand is simply zero. The likelihood that half of them would is also zero, I believe. The worst case scenario is that abortion would become geographically inconvenient. (In case you wonder, I believe, just like former President Bill Clinton, that abortion should be legal, safe, and rare.) There is no chance that not electing Mrs Clinton will make abortion illegal.

Pay disparities

We have been told that women received interior pay for equal work for so long that it has almost become the truth. Even my local female Republican candidate for Congress uses this line. It’s not the truth. The reality is that women receive unequal pay for unequal work. There are various reasons why this is. (A broader treatment of this matter is on my blog and accessible through these two links.) In fact, paying women unequal pay for equal work has been against federal law for more than thirty years. Doing it is an invitation to costly class action suits. It’s probably important not to vote for someone on the basis of “facts” that are not facts at all. And then, there is the issue of why anyone would mislead you so badly. (Myself, I am going to vote for the Republican lady candidate for Congress although I think she should check her facts better.)


Candidate Clinton has said clearly that she is is for open borders. This may come from a generous heart. Yet there are too many people from poor countries who want to come to the US to live. Even, if all of them are good people, the USA is like a lifeboat: If too many climb aboard, the boat capsizes and everybody drowns, the original passengers (Americans as well as existing immigrants) and the newcomers (would-be immigrants). To remain a decent society, a generous society, the US has to somehow restrict admission. Open borders is not a possible policy, it’s a dangerous fantasy. (In case you are wondering: I am an immigrant myself, so is my wife.)


Candidate Trump bragged – thirteen years ago – about making crude sexual gestures. There has not been a single formal complaint or any charge brought against him on this account. That’s although – unlike former Pres. Bill Clinton at the same stage – he has temptingly deep pockets, the kind of pockets that would give fighting courage to any moderately aggressive attorney. Candidate Trump often also has a filthy mouth, and he occasionally uses sexist language, that’s a fact. Candidate Clinton is good friends with and approves of, and patronizes artists who routinely sing of perpetrating gross sexual violence on women (including in the last days of her campaign). They too use obscene words. They do so routinely, every time they perform. (I don’t use such language myself but my wife of forty years does, another story, obviously.)

Please share this and ask your friends to share.

BC’s weekend reads

  1. NATO sends a message to Russia
  2. Iraq doesn’t need to break up to be successful (so says a scholar at Brookings)
  3. Benedict Anderson (political science) reviews Clifford Geertz (anthropology)
  4. The Muddled Mystique of Karl Polanyi
  5. The prison house of gender
  6. Investigating Madison’s Political Religion (central planning is hard to do)

New issue of Econ Journal Watch is out!

For those of you who don’t already know, Warren is the math reader for EJW and one of NOL‘s co-founders, Fred Foldvary, is an editor for the journal, so this is very much a family affair. Here are some of the articles that caught my eye:

You get what you measure: Daniel Schwekendiek explains how South Korea followed a proven template of incentivizing exports to boost Web of Science publications and raise the rankings of its academic institutions.

Now entering a Republican-free zone: Mitchell Langbert, Anthony J. Quain, and Daniel Klein report on the voter registration of faculty at 40 leading U.S. universities in Economics, History, Journalism, Law, and Psychology.

Whither science in gender sociology? Charlotta Stern investigates whether gender sociologists blinker themselves from scientific findings about sex differences.

How to Do Well by Doing Good! In this 1984 essay, Gordon Tullock counsels young economists that doing well and doing good go together.

You can download and read the whole thing here (pdf).