Tuesday, 6 February 2018

Loss aversion, ideology and the peer review process

Last month, Andrew Gelman wrote an interesting blog post about peer review, or more accurately about how researchers steer their papers through the peer review process:
...researchers are taught to be open to new ideas, research is all about finding new things and being aware of flaws in existing paradigms—but researchers can be sooooo reluctant to abandon their own pet ideas...
My story goes like this. As scientists, we put a lot of effort into writing articles, typically with collaborators: we work hard on each article, try to get everything right, then we submit to a journal.
What happens next? Sometimes the article is rejected outright, but, if not, we’ll get back some review reports which can have some sharp criticisms: What about X? Have you considered Y? Could Z be biasing your results? Did you consider papers U, V, and W?
The next step is to respond to the review reports, and typically this takes the form of, We considered X, and the result remained significant. Or, We added Y to the model, and the result was in the same direction, marginally significant, so the claim still holds. Or, We adjusted for Z and everything changed . . . hmmmm . . . we then also though about factors P, Q, and R. After including these, as well as Z, our finding still holds. And so on.
The point is: each of the remarks from the reviewers is potentially a sign that our paper is completely wrong, that everything we thought we found is just an artifact of the analysis, that maybe the effect even goes in the opposite direction! But that’s typically not how we take these remarks. Instead, almost invariably, we think of the reviewers’ comments as a set of hoops to jump through: We need to address all the criticisms in order to get the paper published. 
Gelman argues that there is a problem with the way that researchers are trained to deal with peer review. Researchers deal with peer review by making the minimal number of changes necessary in order to ensure publication, Gelman argues that that needs to change. I don't disagree. However, I think he is missing something important about researchers, as real people.

People are loss averse. We value losses much more than equivalent gains (in other words, we like to avoid losses much more than we like to capture equivalent gains). Loss aversion makes people subject to the endowment effect - we are unwilling to give up something that we already have, because then we would face a loss (and we are loss averse). Or at least, there would have to be a big offsetting gain in order to convince us to give something up that we already have. The endowment effect applies to objects (the original Richard Thaler experiment that demonstrated endowment effects gave people coffee mugs), but it also applies to ideas.

I've thought for a long time that ideology was simply an extreme example of the endowment effect and loss aversion in practice. Haven't you ever wondered why it's so difficult to convince some people of the rightness of your way of thinking? It's because, in order for them to agree with you, that other person would have to give up their own way of thinking, and that would be a loss (and they are loss averse). It seems unlikely that the benefits of agreeing with you are enough to offset the loss they feel from giving up their prior beliefs, at least for some people. Once you consider loss aversion, it's easy to see how ideologies can become entrenched. An ideology is simply lots of people suffering from loss aversion and the endowment effect.

Now, back to peer review. Researchers are also loss averse, and when they submit an article for publication, the article includes their own ideas, analysis, and conclusions. They don't want to give those up, since that would be a loss (and researchers, like everyone else, want to avoid losses). So, it is natural for researchers to deal with reviewers' comments in a way that minimises the sense of loss that they feel from making the necessary changes (while preserving the gains from getting the article finally published). Making small, incremental changes to a research paper minimises the loss the researchers feel, and so that is the way that researchers deal with peer review.

How to solve the problem? Gelman's solution appears to be better training for researchers. However, I can't see how you can train someone out of being loss averse, which means that we are stuck with researchers who will, as Gelman says, "respond to legitimate scientific criticism in an angry, defensive, closed, non-scientific way". Maybe instead it's time to reconsider peer review? Maybe peer review should exist only to screen out the most egregious errors and not to quibble over minor details (most of which can easily be quibbled over later in online commentary on the paper)?


Sunday, 4 February 2018

Book Review: Beauty Pays

I've written a couple of times about the effects of beauty on economic outcomes (see here and here). So, I was quite interested to read Daniel Hamermesh's 2011 book Beauty Pays: Why Attractive People are More Successful. Hamermesh is the godfather of this strand of the labour economics literature, having been involved in many of the key studies. This is a book where he lays out the state of the literature (as it was in 2011, although it might be fair to say that it hasn't moved on a whole lot since).

The book covers some key themes. First among these is expressed in the title of the book: beauty pays. Those who are more attractive earn a wage premium compared with those who are less attractive. By now, this finding is incontrovertible, although still controversial. How big is the premium? Hamermesh notes that the effect of good looks on earnings for men is about the same as an additional one and a half years of education, or five years of work experience. The premium for women is about two-thirds as large. When expressed over a lifetime, the difference between a good-looking and a bad-looking worker is about US$230,000 in lifetime earnings. So, it's not a small effect, but again it is less for women.

I know some of you will be wondering why the beauty premium is lower for women (as with many of you, I would have thought it would be larger). Hamermesh explains that:
...one explanation for the surprisingly larger effect of looks on men's than on women's earnings is that women have much more latitude than men in choosing whether or not to work for pay, and that beauty affects that choice. Part of the reason for the gender difference in the effects of beauty on earnings is that beauty alters the mix of female workers, so that the distribution of workers contains proportionately fewer below-average looking women. That is less true for men.
In other words, the less-good-looking women are less likely to work at all (compared with less-good-looking men), which means the difference between good-looking and less-good-looking women in terms of observed wages is reduced compared with the difference between good-looking and less-good-looking men.

Hamermesh then gives an excellent discussion of reasons why the beauty premium may arise due to the actions of employers. The overall discussion is difficult to excerpt, but this bit in particular caught my attention:
If we think of looks as part of a product or service, and if we assume that potential customers value looks, then it is clear how better-looking employees can raise a competitive company's sales. At the same average cost of all the other inputs into the product and at the same price charged, customers will be more likely to buy the product and/or will be willing to buy more of it. More will be sold; and the company will expand at the expense of its competitors.
It is a similar argue to one my wife is making in her PhD thesis about the work of baristas and how consumers consume the product (coffee) as well as the experience, which includes the emotional labour of the barista. Both aspects are valued by the customer.

However, there are a couple of parts of the book where I must disagree with Hamermesh. He argues that the beauty premium is socially productive, i.e. that it is associated with greater economic output and production, since good looking workers are more likely to sell things than less-good-looking workers. I'm less convinced on this point, since it ignores the fact that the beauty premium dissuades some workers from working entirely (see the paragraph on gender differences above). So, while the beauty premium might increase sales, it also has an offsetting negative impact on economic output and it isn't clear which effect (positive or negative) would be larger.

Most of the time, Hamermesh addresses any concerns I have with the book in the later chapters. He finishes the book with arguments for why ugly workers should be protected, which relies on an assumption that the cost of such a policy (through reducing the beauty premium, which is socially productive) would be outweighed by benefits to ugly workers. Again, I'm unconvinced, but there is plenty of scope for future research to address that question as there is little evidence in either direction. Hamermesh does note that helping ugly workers may come with unintended opportunity costs:
Put in stark terms, aiding workers in one disadvantaged group tends to reduce wages and take jobs away from those in other disadvantaged groups.
In that case, maybe it is better not to help ugly workers?

Overall, if you are interested in the economics of beauty, this is a great place to start. Hamermesh does an excellent job of covering the literature. Regardless of whether you agree or disagree with the normative conclusions he draws, this book is a good read.

Saturday, 3 February 2018

The overstated impact of the Super Bowl

Super Bowl LII will be played in a couple of days, between the Eagles and Patriots (and with my Panthers out of the running, I'll be backing the Eagles - the Patriots have had their fill of success in recent years). Tens of thousands of fans have descended on Minneapolis for the game, and accommodation providers, hospitality businesses, and retailers will no doubt see increased sales as a result. However, there is another neglected group that benefits greatly from large sporting events - the consultants who write economic impact studies, and charge thousands of dollars for them. As I've written about before (most recently in terms of the America's Cup), most economic impact studies are junk, or at the very least heavily overstate the benefits. Kevin Draper made the case for recently in the New York Times, related to the economic impact of the Super Bowl:
Depending on what, exactly, constitutes a public dollar, taxpayers contribute an average of about $250 million to build N.F.L. stadiums, according to the advisory firm Conventions, Sports & Leisure International. For U.S. Bank Stadium in Minneapolis — which opened in 2016 and will host the Super Bowl on Sunday — the state of Minnesota spent $348 million and the city kicked in an additional $150 million, a bit less than 50 percent of the stadium’s total cost.
An economic impact report commissioned by the Minneapolis Super Bowl Host Committee stated that much of the taxpayer investment in the stadium would be recouped by the region during the event. It estimated that the Super Bowl would contribute $343 million to the region, including $29 million in tax revenue.
“We are taking a conservative approach with the numbers,” Michael Langley, the chief executive of the Minneapolis-St. Paul economic development agency, said. “But even if you are only talking about $350 million to $400 million, that’s a huge benefit to the community, just in terms of dollars spent in February.”
Sports economists don’t view the situation quite the same way. They said the economic impact study for the Minneapolis Super Bowl began by saying all the right things about how past estimates had “been criticized as extremely overinflated, inaccurate, even purposely misrepresented.” In the end, though, it did the same thing.
The main problem, usually, with economic impact studies is the incorrect specification of a counterfactual - what would have happened if the event (e.g. the Super Bowl) hadn't happened? In most cases, there wouldn't have been no visitors to the area, so it's inappropriate to suggest that all economic activity during or around the event represents extra economic activity. Draper notes:
Take hotel rooms, for example. To host the Super Bowl, Minneapolis had to show that there were at least 24,000 of them within 60 minutes of the stadium, capable of accommodating visitors during the entire 10-day Super Bowl celebration. Accordingly, the economic impact report estimates the Super Bowl will generate 230,000 nights of hotel stays.
But if the Super Bowl were not in town, many of those hotel rooms would have been filled anyway, by business travelers, conventiongoers and — yes, even in Minnesota in the dead of winter — tourists.
A related example, and closer to home. The World Sevens Series is being played in my city (Hamilton) today. My wife and I were thinking about going out for dinner in town last night, but wisely thought better of it when we considered how busy it was likely to be. The restaurant probably gained custom from the rugby fans here for the weekend, but they also lost the custom from my wife and I.

Draper also raises another good point:
The rooms cost more than they otherwise would, generating about $28 million in additional revenue. But Stephenson cautioned against assuming that the money had stayed in Indianapolis; in fact, there was heavy leakage.
“They don’t give it to the housekeeper or bellboy or front-desk person,” he said. “A lot of it just flows to whoever owns the hotel.”
To suggest that all of the benefit of additional spending in the city is a benefit to the city is to ignore where the profits will go. That's an even more important consideration for events in New Zealand, where a significant proportion of profits may be siphoned off by international hotel chains, travel providers, and so on.

In any case, it's a good reminder that we should be careful what we believe when we are presented with big numbers that are labelled 'economic impact'. Including when we read the forthcoming "independent economic report" for the Hamilton Sevens (mentioned here).

Thursday, 1 February 2018

Some further notes on rent increases

Rent increases have been in the news a lot recently, especially in Wellington (see my post from earlier in the week). Based on some discussions with students, I thought I would make a few notes.

First, some have suggested that rents have increased by $50 because student allowances and Student Loan living cost payments have increased by that much (e.g. Grant Robertson's Facebook post on this). This is possible, but unlikely. If our incomes increase, we will be willing to pay more for rental housing (rental housing is what economists call a 'normal good'). That shifts our demand curve for housing up and to the right, as in the diagram below (from D0 to D1). The equilibrium rent will increase from R0 to R1. How much more will be willing to pay, and how much will the equilibrium rent increase by? Certainly our willingness-to-pay will not increase by the whole additional $50 of our income, because when our incomes increase we are also willing to pay more for food, clothing, entertainment, and all of the other normal goods that we like to buy. Our willingness-to-pay for rent will increase by some proportion of the $50 increase in income. So, I think it's extraordinarily unlikely that an increase in demand, driven by the increase in incomes, is solely behind the increase in rent.


Second, prices increase when there is excess demand. Is excess demand driving the increase in rents by $50? I covered this in my post on Monday and Eric Crampton also covered it. It's possible that rents are currently below the equilibrium rent, as shown in the diagram below. At the rent R0, there are Qd tenants looking for a house, but only Qs houses available to rent. There is excess demand for housing. Some tenants are missing out on housing. Landlords and tenants both recognise the excess demand, and tenants might start approaching landlords and offering a bit more in order not to miss out, or landlords might increase rents knowing that tenants will be willing to pay a little bit more in order not to miss out. Either way, rents start to rise and eventually the market ends up at the higher equilibrium rent R1. However, we seem to be in a perpetual state of excess demand in the rental market (if you doubt that, look at any of my past posts on housing). I've mused that maybe landlords are offering 'efficiency rents' - rents that are deliberately below the equilibrium rent, because that allows them to have the pick of applicants. So, I think it unlikely that excess demand is a big factor in increasing rents.


Third, and something that I haven't seen anybody considering, is that the accommodation supplement will increase on 1 April. Landlords signing rental agreements now must know that the accommodation supplement will increase during the term of the tenancy agreement, and that this increase in subsidy works sort of like the increase in demand shown above. However, in the case of the accommodation supplement, we can be fairly sure that it does increase willingness-to-pay for housing by $50, because it can't be used for anything else. [*] Why adjust rents now, when the accommodation supplement doesn't change for two more months? Because the rent that is agreed now can't be changed for several months after April - it makes sense to build this increase in now. This is shown in the diagram below. The accommodation supplement is a subsidy, paid to the tenant, so we show this with the D+subsidy curve, which is above the demand curve (for simplicity, the diagram doesn't show an increase in an existing accommodation supplement, which is actually what is happening, but making the diagram a bit more complex doesn't change the story at all). Another way of thinking about this is that, once the accommodation supplement increases by $50, households are willing to pay the same as before (shown by the demand curve), plus the extra $50 of the increased accommodation supplement. The rent before the increase in the accommodation supplement is R0. After the increase in the accommodation supplement, the rent that households pay to the landlords increases to RL, and the effective rent (after subtracting the increase in the accommodation supplement) falls to RT. Notice that most of the benefit of the increased accommodation supplement is captured by landlords. This is because of the very steep (inelastic) supply curve in the rental market - when rents increase, there aren't a lot of additional landlords rushing to make their houses available for renting.


So, my feeling is that the increase in rents we are observing now is the effect of landlords recognising that the accommodation supplement will soon increase, and they are trying to capture that increase early. And not the effect of the increase in student allowances, or excess demand for rental housing. Or maybe it is a little bit of all three? Of course, the easiest way to find out whether this explanation is the right one would be to ask landlords. But given the potential for a media beat-up, would you really expect them to come clean about this?

Finally, some dimwits have been advocating for rent controls (see Anna Mooney of Renters United quoted here). No. Just no.

Read more:

*****

[*] You may be thinking here that income is fungible (it can be used for other things besides housing). That means that, when the accommodation supplement increases by $50, households' willingness-to-pay for housing might not increase by $50, because they might re-direct some of their other intended spending away from housing. However, in a world where people are quasi-rational and affected by mental accounting, it turns out that fungibility may actually be reasonably low (I'm currently reading Richard Thaler's excellent book Misbehaving: The Making of Behavioral Economics - more on that when I review it soon). Quasi-rational decision-makers have a household budget for rent, and when the accommodation supplement increases by $50, they may be thinking that means they can spend $50 more on rent (rather than other things) and act accordingly.