Reasonableness and public goods games

Apr 1 JDN 2458210

There’s a very common economics experiment called a public goods game, often used to study cooperation and altruistic behavior. I’m actually planning on running a variant of such an experiment for my second-year paper.

The game is quite simple, which is part of why it is used so frequently: You are placed into a group of people (usually about four), and given a little bit of money (say $10). Then you are offered a choice: You can keep the money, or you can donate some of it to a group fund. Money in the group fund will be multiplied by some factor (usually about two) and then redistributed evenly to everyone in the group. So for example if you donate $5, that will become $10, split four ways, so you’ll get back $2.50.

Donating more to the group will benefit everyone else, but at a cost to yourself. The game is usually set up so that the best outcome for everyone is if everyone donates the maximum amount, but the best outcome for you, holding everyone else’s choices constant, is to donate nothing and keep it all.

Yet it is a very robust finding that most people do neither of those things. There’s still a good deal of uncertainty surrounding what motivates people to donate what they do, but certain patterns that have emerged:

  1. Most people donate something, but hardly anyone donates everything.
  2. Increasing the multiplier tends to smoothly increase how much people donate.
  3. The number of people in the group isn’t very important, though very small groups (e.g. 2) behave differently from very large groups (e.g. 50).
  4. Letting people talk to each other tends to increase the rate of donations.
  5. Repetition of the game, or experience from previous games, tends to result in decreasing donation over time.
  6. Economists donate less than other people.

Number 6 is unfortunate, but easy to explain: Indoctrination into game theory and neoclassical economics has taught economists that selfish behavior is efficient and optimal, so they behave selfishly.

Number 3 is also fairly easy to explain: Very small groups allow opportunities for punishment and coordination that don’t exist in large groups. Think about how you would respond when faced with 2 defectors in a group of 4 as opposed to 10 defectors in a group of 50. You could punish the 2 by giving less next round; but punishing the 10 would end up punishing 40 others who had contributed like they were supposed to.

Number 4 is a very interesting finding. Game theory says that communication shouldn’t matter, because there is a unique Nash equilibrium: Donate nothing. All the promises in the world can’t change what is the optimal response in the game. But in fact, human beings don’t like to break their promises, and so when you get a bunch of people together and they all agree to donate, most of them will carry through on that agreement most of the time.

Number 5 is on the frontier of research right now. There are various theoretical accounts for why it might occur, but none of the models proposed so far have much predictive power.

But my focus today will be on findings 1 and 2.

If you’re not familiar with the underlying game theory, finding 2 may seem obvious to you: Well, of course if you increase the payoff for donating, people will donate more! It’s precisely that sense of obviousness which I am going to appeal to in a moment.

In fact, the game theory makes a very sharp prediction: For N players, if the multiplier is less than N, you should always contribute nothing. Only if the multiplier becomes larger than N should you donate—and at that point you should donate everything. The game theory prediction is not a smooth increase; it’s all-or-nothing. The only time game theory predicts intermediate amounts is on the knife-edge at exactly equal to N, where each player would be indifferent between donating and not donating.

But it feels reasonable that increasing the multiplier should increase donation, doesn’t it? It’s a “safer bet” in some sense to donate $1 if the payoff to everyone is $3 and the payoff to yourself is $0.75 than if the payoff to everyone is $1.04 and the payoff to yourself is $0.26. The cost-benefit analysis comes out better: In the former case, you can gain up to $2 if everyone donates, but would only lose $0.25 if you donate alone; but in the latter case, you would only gain $0.04 if everyone donates, and would lose $0.74 if you donate alone.

I think this notion of “reasonableness” is a deep principle that underlies a great deal of human thought. This is something that is sorely lacking from artificial intelligence: The same AI that tells you the precise width of the English Channel to the nearest foot may also tell you that the Earth is 14 feet in diameter, because the former was in its database and the latter wasn’t. Yes, WATSON may have won on Jeopardy, but it (he?) also made a nonsensical response to the Final Jeopardy question.

Human beings like to “sanity-check” our results against prior knowledge, making sure that everything fits together. And, of particular note for public goods games, human beings like to “hedge our bets”; we don’t like to over-commit to a single belief in the face of uncertainty.

I think this is what best explains findings 1 and 2. We don’t donate everything, because that requires committing totally to the belief that contributing is always better. We also don’t donate nothing, because that requires committing totally to the belief that contributing is always worse.

And of course we donate more as the payoffs to donating more increase; that also just seems reasonable. If something is better, you do more of it!

These choices could be modeled formally by assigning some sort of probability distribution over other’s choices, but in a rather unconventional way. We can’t simply assume that other people will randomly choose some decision and then optimize accordingly—that just gives you back the game theory prediction. We have to assume that our behavior and the behavior of others is in some sense correlated; if we decide to donate, we reason that others are more likely to donate as well.

Stated like that, this sounds irrational; some economists have taken to calling it “magical thinking”. Yet, as I always like to point out to such economists: On average, people who do that make more money in the games. Economists playing other economists always make very little money in these games, because they turn on each other immediately. So who is “irrational” now?

Indeed, if you ask people to predict how others will behave in these games, they generally do better than the game theory prediction: They say, correctly, that some people will give nothing, most will give something, and hardly any will give everything. The same “reasonableness” that they use to motivate their own decisions, they also accurately apply to forecasting the decisions of others.

Of course, to say that something is “reasonable” may be ultimately to say that it conforms to our heuristics well. To really have a theory, I need to specify exactly what those heuristics are.

“Don’t put all your eggs in one basket” seems to be one, but it’s probably not the only one that matters; my guess is that there are circumstances in which people would actually choose all-or-nothing, like if we said that the multiplier was 0.5 (so everyone giving to the group would make everyone worse off) or 10 (so that giving to the group makes you and everyone else way better off).

“Higher payoffs are better” is probably one as well, but precisely formulating that is actually surprisingly difficult. Higher payoffs for you? For the group? Conditional on what? Do you hold others’ behavior constant, or assume it is somehow affected by your own choices?

And of course, the theory wouldn’t be much good if it only worked on public goods games (though even that would be a substantial advance at this point). We want a theory that explains a broad class of human behavior; we can start with simple economics experiments, but ultimately we want to extend it to real-world choices.

Hyperbolic discounting: Why we procrastinate

Mar 25 JDN 2458203

Lately I’ve been so occupied by Trump and politics and various ideas from environmentalists that I haven’t really written much about the cognitive economics that was originally planned to be the core of this blog. So, I thought that this week I would take a step out of the political fray and go back to those core topics.

Why do we procrastinate? Why do we overeat? Why do we fail to exercise? It’s quite mysterious, from the perspective of neoclassical economic theory. We know these things are bad for us in the long run, and yet we do them anyway.

The reason has to do with the way our brains deal with time. We value the future less than the present—but that’s not actually the problem. The problem is that we do so inconsistently.

A perfectly-rational neoclassical agent would use time-consistent discounting; what this means is that the effect of a given time interval won’t change or vary based on the stakes. If having $100 in 2019 is as good as having $110 in 2020, then having $1000 in 2019 is as good as having $1100 in 2020; and if I ask you in 2019, you’ll still agree that having $100 in 2019 is as good as having $1100 in 2020. A perfectly-rational individual would have a certain discount rate (in this case, 10% per year), and would apply it consistently at all times on all things.

This is of course not how human beings behave at all.

A much more likely pattern is that you would agree, in 2018, that having $100 in 2019 is as good as having $110 in 2020 (a discount rate of 10%). But then if I wait until 2019, and then offer you the choice between $100 immediately and $120 in a year, you’ll probably take the $100 immediately—even though a year ago, you told me you wouldn’t. Your discount rate rose from 10% to at least 20% in the intervening time.

The leading model in cognitive economics right now to explain this is called hyperbolic discounting. The precise functional form of a hyperbola has been called into question by recent research, but the general pattern is definitely right: We act as though time matters a great deal when discussing time intervals that are close to us, but treat time as unimportant when discussing time intervals that are far away.

How does this explain procrastination and other failures of self-control over time? Let’s try an example.

Let’s say that you have a project you need to finish by the end of the day Friday, which has a benefit to you, received on Saturday, that I will arbitrarily scale at 1000 utilons.

Then, let’s say it’s Monday. You have five days to work on it, and each day of work costs you 100 utilons. If you work all five days, the project will get done.

If you skip a day of work, you will need to work so much harder that one of the following days your cost of work will be 300 utilons instead of 100. If you skip two days, you’ll have to pay 300 utilons twice. And if you skip three or more days, the project will not be finished and it will all be for naught.

If you don’t discount time at all (which, over a week, is probably close to optimal), the answer is obvious: Work all five days. Pay 100+100+100+100+100 = 500, receive 1000. Net benefit: 500.

But even if you discount time, as long as you do so consistently, you still wouldn’t procrastinate.

Let’s say your discount rate is extremely high (maybe you’re dying or something), so that each day is only worth 80% as much as the previous. Benefit that’s worth 1 on Monday is worth 0.8 if it comes on Tuesday, 0.64 if it comes on Wednesday, 0.512 if it comes on Thursday, 0.4096 if it comes on Friday,a and 0.32768 if it comes on Saturday. Then instead of paying 100+100+100+100+100 to get 1000, you’re paying 100+80+64+51+41=336 to get 328. It’s not worth doing the project; you should just enjoy your last few days on Earth. That’s not procrastinating; that’s rationally choosing not to undertake a project that isn’t worthwhile under your circumstances.

Procrastinating would look more like this: You skip the first two days, then work 100 the third day, then work 300 each of the last two days, finishing the project. If you didn’t discount at all, you would pay 100+300+300=700 to get 1000, so your net benefit has been reduced to 300.

There’s no consistent discount rate that would make this rational. If it was worth giving up 200 on Thursday and Friday to get 100 on Monday and Tuesday, you must be discounting at least 26% per day. But if you’re discounting that much, you shouldn’t bother with the project at all.

There is however an inconsistent discounting by which it makes perfect sense. Suppose that instead of consistently discounting some percentage each day, psychologically it feels like this: The value is the inverse of the length of time (that’s what it means to be hyperbolic). So the same amount of benefit on Monday which is worth 1 is only worth 1/2 if it comes on Tuesday, 1/3 if on Wednesday, 1/4 if on Thursday, and 1/5 if on Friday.

So, when thinking about your weekly schedule, you realize that by pushing back Monday’s work to Thursday, you can gain 100 today at a cost of only 200/4 = 50, since Thursday is 4 days away. And by pushing back Tuesday’s work to Friday, you can gain 100/2=50 today at a cost of only 200/5=40. So now it makes perfect sense to have fun on Monday and Tuesday, start working on Wednesday, and cram the biggest work into Thursday and Friday. And yes, it still makes sense to do the project, because 1000/6 = 166 is more than the 100/3+200/4+200/5 = 123 it will cost to do the work.

But now think about what happens when you come to Wednesday. The work today costs 100. The work on Thursday costs 200/2 = 100. The work on Friday costs 200/3 = 66. The benefit of completing the project will be 1000/4 = 250. So you are paying 100+100+66=266 to get a benefit of only 250. It’s not worth it anymore! You’ve changed your mind. So you don’t work Wednesday.

At that point, it’s too late, so you don’t work Thursday, you don’t work Friday, and the project doesn’t get done. You have procrastinated away the benefits you could have gotten from doing this project. If only you could have done the work on Monday and Tuesday, then on Wednesday it would have been worthwhile to continue: 100/1+100/2+100/3 = 183 is less than the benefit of 250.

What went wrong? The key event was the preference reversal: While on Monday you preferred having fun on Monday and working on Thursday to working on both days, when the time came you changed your mind. Someone with time-consistent discounting would never do that; they would either prefer one or the other, and never change their mind.

One way to think about this is to imagine future versions of yourself as different people, who agree with you on most things, but not on everything. They’re like friends or family; you want the best for them, but you don’t always see eye-to-eye.

Generally we find that our future selves are less rational about choices than we are. To be clear, this doesn’t mean that we’re all declining in rationality over time. Rather, it comes from the fact that future decisions are inherently closer to our future selves than they are to our current selves, and the closer a decision gets the more likely we are to use irrational time discounting.

This is why it’s useful to plan and make commitments. If starting on Monday you committed yourself to working every single day, you’d get the project done on time and everything would work out fine. Better yet, if you committed yourself last week to starting work on Monday, you wouldn’t even feel conflicted; you would be entirely willing to pay a cost of 100/8+100/9+100/10+100/11+100/12=51 to get a benefit of 1000/13=77. So you could set up some sort of scheme where you tell your friends ahead of time that you can’t go out that week, or you turn off access to social media sites (there are apps that will do this for you), or you set up a donation to an “anti-charity” you don’t like that will trigger if you fail to complete the project on time (there are websites to do that for you).

There is even a simpler way: Make a promise to yourself. This one can be tricky to follow through on, but if you can train yourself to do it, it is extraordinarily powerful and doesn’t come with the additional costs that a lot of other commitment devices involve. If you can really make yourself feel as bad about breaking a promise to yourself as you would about breaking a promise to someone else, then you can dramatically increase your own self-control with very little cost. The challenge lies in actually cultivating that sort of attitude, and then in following through with making only promises you can keep and actually keeping them. This, too, can be a delicate balance; it is dangerous to over-commit to promises to yourself and feel too much pain when you fail to meet them.
But given the strong correlations between self-control and long-term success, trying to train yourself to be a little better at it can provide enormous benefits.
If you ever get around to it, that is.

And so begins the trade war Trump promised us.

Mar 18 JDN 2458196

President Trump (a phrase I will never quite feel comfortable saying) has used an obscure loophole in US trade law to impose huge tariffs on steel and aluminum. The loophole is based on the idea that certain goods are vital for national security, and therefore imposing tariffs on them is in some sense the proper role of the Commander in Chief. It’s a pretty flimsy justification in general (if it’s really so important, why can’t Congress do it?), and particularly so in this case: Most of our steel and aluminum comes from Canada, and we are still totally dependent on imports for bauxite to make aluminum. Trump did finally cave in on allowing NAFTA members to be exempt, so Canada won’t be paying the tariff. The only country that could plausibly be considered an enemy that will be meaningfully affected by the tariffs is (ironically) Russia.

The European Union has threatened to respond with their own comparable tariffs—meaning that a trade war has officially begun. The last time the US started a major trade war was in 1930—which you may recognize as the start of the Great Depression. There’s a meme going around saying that 1928 was the last time the Republican Party controlled the whole US government; that isn’t actually true. Republicans have controlled all three branches as recently as 2006. Of course, the late 2000s weren’t a great time for the US economy either, so make of that what you will.

Does this mean we’re headed toward another Great Depression? I don’t think so. Our monetary policy is vastly better now than it was then. But are we headed toward another recession? That seems quite likely. By standard measures, the stock market is overvalued. The unemployment rate is now at 4%. We are basically at the ceiling right now; the only place to go is down.

Of course, maybe we will stay here awhile. We don’t have to go down, necessarily. If Obama were still President and Yellen were still Fed Chair, I might believe that. But the level of corruption, incompetence, and ideological rigidity in Trump’s economic policy is something I’ve not seen in the United States within my lifetime.

Peter Navarro, Trump’s Director of the White House Trade Council, has described his own role in an incredibly chilling way:

“This is the president’s vision. My function, really, as an economist is to try to provide the underlying analytics that confirm his intuition. And his intuition is always right in these matters. […] The owner, the coach, and the quarterback are all the president. The rest of us are all interchangeable parts.”

Well, there you have it. It’s just as the saying goes: There are liberal professional economists, conservative professional economists, and professional conservative economists. Peter Navarro has officially and proudly declared himself a professional conservative economist. He seems proud to admit that his only function is to rationalize what Trump already believes.

We really shouldn’t be surprised that Trump brought us into a trade war. Frankly, it was one of his campaign promises. When he was announcing the tariffs, he declared, “Trade wars are good, and easy to win.” In fact, trade war is much like real war, in that the only winning move is not to play.

What really worries me about all this isn’t how it will affect the US. Maybe it’ll trigger another recession, sure; but we’ve had lots of those, and we make it through eventually. (Recession might even be good for our carbon emissions, as we’re well above the Wedge.) The US economy is very strong, and can withstand a lot of mistakes. Even on a bad day we’re still the richest country in the world.

What worries me is how it will affect other countries. It’ll start with countries that export steel and aluminum, like India, China and Brazil. But as tariffs and counter-tariffs proliferate, more and more exports will be brought into the trade war. Trade is one of the most powerful tools we have for fighting global poverty, and we are now pulling the plug.

Of course, hurting China was part of Trump’s goal, so I doubt he’ll feel much remorse if the trade war results in millions of people in China thrown back into poverty. People who voted for him on the grounds that he would keep the dirty foreigners down may well be celebrating such an outcome.

There will be pain. But most of it will be felt elsewhere from here. “But those were Foreign children and it didn’t really matter.”

Forget the Doughnut. Meet the Wedge.

Mar 11 JDN 2458189

I just finished reading Kate Raworth’s book Doughnut Economics: Seven Ways to Think Like a 21st-Century Economist; Raworth also has a whole website dedicated to the concept of the Doughnut as a way of rethinking economics.

The book is very easy to read, and manages to be open to a wide audience with only basic economics knowledge without feeling patronizing or condescending. Most of the core ideas are fundamentally sound, though Raworth has a way of making it sound like she is being revolutionary even when most mainstream economists already agree with the core ideas.

For example, she makes it sound like it is some sort of dogma among neoclassical economists that GDP growth must continue at the same pace forever. As I discussed in an earlier post, the idea that growth will slow down is not radical in economics—it is basically taken for granted in the standard neoclassical growth models.

Even the core concept of the Doughnut isn’t all that radical. It’s based on the recognition that economic development is necessary to end poverty, but resources are not unlimited. Then combine that with two key assumptions: GDP growth requires growth in energy consumption, and growth in energy consumption requires increased carbon emissions. Then, the goal should be to stay within a certain range: We want to be high enough to not have poverty, but low enough to not exceed our carbon budget.

Why a doughnut? That’s… actually a really good question. The concept Raworth presents is a fundamentally one-dimensional object; there’s no reason for it to be doughnut-shaped. She could just as well have drawn it on a single continuum, with poverty at one end, unsustainability at the other end, and a sweet spot in the middle. The doughnut shape adds some visual appeal, but no real information.

But the fundamental assumptions that GDP requires energy and energy requires carbon emissions are simply false—especially the second one. Always keep one thing in mind whenever you’re reading something by environmentalists telling you we need to reduce economic output to save the Earth: Nuclear power does not produce carbon emissions.

This is how the environmentalist movement has shot itself—and the world—in the foot for the last 50 years. They continually refuse to admit that nuclear power is the best hope we have for achieving both economic development and ecological sustainability. They have let their political biases cloud their judgment on what is actually best for humanity’s future.

I will give Raworth some credit for not buying into the pipe dream that we can somehow transition rapidly to an entirely solar and wind-based power grid—renewables only produce 6% of world energy (the most they ever have), while nuclear produces 10%. And nuclear power certainly has its downsides, particularly in its high cost of construction. It may in fact be the case that we need to reduce economic output somewhat, particularly in the very richest countries, and if so, we need to find a way to do that without causing social and political collapse.

The Dougnut is a one-dimensional object glorified by a two-dimensional diagram.

So let me present you with an actual two-dimensional object, which I call the Wedge.

On this graph, the orange dots plot actual GDP per capita (at purchasing power parity) on the X axis against actual CO2 emissions per capita on the Y-axis. The green horizonal line is a CO2 emission target of 3 tonnes per person per year based on reports from the International Panel on Climate Change.

Wedge_full

As you can see, most countries are above the green line. That’s bad. We need the whole world below that green line. The countries that are below the line are largely poor countries, with a handful of middle-income countries mixed in.

But it’s the blue diagonal line that really makes this graph significant, what makes it the Wedge. That line uses Switzerland’s level of efficiency to estimate a frontier of what’s possible. Switzerland’s ratio of GDP to CO2 is the best in the world, among countries where the data actually looks reliable. A handful of other countries do better in the data, but for some (Macau) it’s obviously due to poor counting of indirect emissions and for others (Rwanda, Chad, Burundi) we just don’t have good data at all. I think Switzerland’s efficiency level of $12,000 per ton of CO2 is about as good as can be reasonably expected for most countries over the long run.

Our goal should be to move as far right on the graph as we can (toward higher levels of economic development), but always staying inside this Wedge: Above the green line, our CO2 emissions are too high. Below the blue line may not be technologically feasible (though of course it’s worth a try). We want to aim for the point of the wedge, where GDP is as high as possible but emissions are still below safe targets.

Zooming in on the graph gives a better view of the Wedge.

Wedge_zoomed

The point of the Wedge is about $38,000 per person per year. This is not as rich as the US, but it’s definitely within the range of highly-developed countries. This is about the same standard of living as Italy, Spain, or South Korea. In fact, all three of these countries exceed their targets; the closest I was able to find to a country actually hitting the point of the wedge was Latvia, at $27,300 and 3.5 tonnes per person per year. Uruguay also does quite well at $22,400 and 2.2 tonnes per person per year.

Some countries are within the Wedge; a few, like Uruguay, quite close to the point, and many, like Colombia and Bangladesh, that are below and to the left. For these countries, a “stay the course” policy is the way to go: If they keep up what they are doing, they can continue to experience economic growth without exceeding their emission targets.

 

But the most important thing about the graph is not actually the Wedge itself: It’s all the countries outside the Wedge, and where they are outside the Wedge.

There are some countries, like Sweden, France, and Switzerland, that are close to the blue line but still outside the Wedge because they are too far to the right. These are countries for whom “degrowth” policies might actually make sense: They are being as efficient in their use of resources as may be technologically feasible, but are simply producing too much output. They need to find a way to scale back their economies without causing social and political collapse. My suggestion, for what it’s worth, is progressive taxation. In addition to carbon taxes (which are a no-brainer), make income taxes so high that they start actually reducing GDP, and do so without fear, since that’s part of the point; then redistribute all the income as evenly as possible so that lower total income comes with much lower inequality and the eradication of poverty. Most of the country will then be no worse off than they were, so social and political unrest seems unlikely. Call it “socialism” if you like, but I’m not suggesting collectivization of industry or the uprising of the proletariat; I just want everyone to adopt the income tax rates the US had in the 1950s.

But most countries are not even close to the blue line; they are well above it. In all these countries, the goal should not be to reduce economic output, but to increase the carbon efficiency of that output. Increased efficiency has no downside (other than the transition cost to implement it): It makes you better off ecologically without making you worse off economically. Bahrain has about the same GDP per capita as Sweden but produces over five times the per-capita carbon emissions. Simply by copying Sweden they could reduce their emissions by almost 19 tonnes per person per year, which is more than the per-capita output of the US (and we’re hardly models of efficiency)—at absolutely no cost in GDP.

Then there are countries like Mongolia, which produces only $12,500 in GDP but 14.5 tonnes of CO2 per person per year. Mongolia is far above and to the left of the point of the Wedge, meaning that they could both increase their GDP and decrease their emissions by adopting the model of more efficient countries. Telling these countries that “degrowth” is the answer is beyond perverse—cut Mongolia’s GDP by 2/3 and you would throw them into poverty without even bringing carbon emissions down to target.

We don’t need to overthrow capitalism or even give up on GDP growth in general. We need to focus on carbon, carbon, carbon: All economic policy from this point forward should be made with CO2 reduction in mind. If that means reducing GDP, we may have to accept that; but often it won’t. Switching to nuclear power and public transit would dramatically reduce emissions but need have no harmful effect on economic output—in fact, the large investment required could pull a country out of recession.

Don’t worry about the Doughnut. Aim for the point of the Wedge.

Is grade inflation a real problem?

Mar 4 JDN 2458182

You can’t spend much time teaching at the university level and not hear someone complain about “grade inflation”. Almost every professor seems to believe in it, and yet they must all be participating in it, if it’s really such a widespread problem.

This could be explained as a collective action problem, a Tragedy of the Commons: If the incentives are always to have the students with the highest grades—perhaps because of administrative pressure, or in order to get better reviews from students—then even if all professors would prefer a harsher grading scheme, no individual professor can afford to deviate from the prevailing norms.

But in fact I think there is a much simpler explanation: Grade inflation doesn’t exist.

In economic growth theory, economists make a sharp distinction between inflation—increase in prices without change in underlying fundamentals—and growth—increase in the real value of output. I contend that there is no such thing as grade inflation—what we are in fact observing is grade growth.
Am I saying that students are actually smarter now than they were 30 years ago?

Yes. That’s exactly what I’m saying.

But don’t take it from me. Take it from the decades of research on the Flynn Effect: IQ scores have been rising worldwide at a rate of about 0.3 IQ points per year for as long as we’ve been keeping good records. Students today are about 10 IQ points smarter than students 30 years ago—a 2018 IQ score of 95 is equivalent to a 1988 score of 105, which is equivalent to a 1958 score of 115. There is reason to think this trend won’t continue indefinitely, since the effect is mainly concentrated at the bottom end of the distribution; but it has continued for quite some time already.

This by itself would probably be enough to explain the observed increase in grades, but there’s more: College students are also a self-selected sample, admitted precisely because they were believed to be the smartest individuals in the application pool. Rising grades at top institutions are easily explained by rising selectivity at top schools: Harvard now accepts 5.6% of applicants. In 1942, Harvard accepted 92% of applicants. The odds of getting in have fallen from 9:1 in favor to 19:1 against. Today, you need a 4.0 GPA, a 36 ACT in every category, glowing letters of recommendation, and hundreds of hours of extracurricular activities (or a family member who donated millions of dollars, of course) to get into Harvard. In the 1940s, you needed a high school diploma and a B average.

In fact, when educational researchers have tried to quantitatively study the phenomenon of “grade inflation”, they usually come back with the result that they simply can’t find it. The US department of education conducted a study in 1995 showing that average university grades had declined since 1965. Given that the Flynn effect raised IQ by almost 10 points during that time, maybe we should be panicking about grade deflation.

It really wouldn’t be hard to make that case: “Back in my day, you could get an A just by knowing basic algebra! Now they want these kids to take partial derivatives?” “We used to just memorize facts to ace the exam; but now teachers keep asking for reasoning and critical thinking?”

More recently, a study in 2013 found that grades rose at the high school level, but fell at the college level, and showed no evidence of losing any informativeness as a signaling mechanism. The only recent study I could find showing genuinely compelling evidence for grade inflation was a 2017 study of UK students estimating that grades are growing about twice as fast as the Flynn effect alone would predict. Most studies don’t even consider the possibility that students are smarter than they used to be—they just take it for granted that any increase in average grades constitutes grade inflation. Many of them don’t even control for the increase in selectivity—here’s one using the fact that Harvard’s average rose from 2.7 to 3.4 from 1960 to 2000 as evidence of “grade inflation” when Harvard’s acceptance rate fell from almost 30% to only 10% during that period.

Indeed, the real mystery is why so many professors believe in grade inflation, when the evidence for it is so astonishingly weak.

I think it’s availability heuristic. Who are professors? They are the cream of the crop. They aced their way through high school, college, and graduate school, then got hired and earned tenure—they were one of a handful of individuals who won a fierce competition with hundreds of competitors at each stage. There are over 320 million people in the US, and only 1.3 million college faculty. This means that college professors represent about the top 0.4% of high-scoring students.

Combine that with the fact that human beings assort positively (we like to spend time with people who are similar to us) and use availability heuristic (we judge how likely something is based on how many times we have seen it).

Thus, when a professor compares to her own experience of college, she is remembering her fellow top-scoring students at elite educational institutions. She is recalling the extreme intellectual demands she had to meet to get where she is today, and erroneously assuming that these are representative of most the population of her generation. She probably went to school at one of a handful of elite institutions, even if she now teaches at a mid-level community college: three quarters of college faculty come from the top one quarter of graduate schools.

And now she compares to the students she has to teach, most of whom would not be able to meet such demands—but of course most people in her generation couldn’t either. She frets for the future of humanity only because not everyone is a genius like her.

Throw in the Curse of Knowledge: The professor doesn’t remember how hard it was to learn what she has learned so far, and so the fact that it seems easy now makes her think it was easy all along. “How can they not know how to take partial derivatives!?” Well, let’s see… were you born knowing how to take partial derivatives?

Giving a student an A for work far inferior to what you’d have done in their place isn’t unfair. Indeed, it would clearly be unfair to do anything less. You have years if not decades of additional education ahead of them, and you are from self-selected elite sample of highly intelligent individuals. Expecting everyone to perform as well as you would is simply setting up most of the population for failure.

There are potential incentives for grade inflation that do concern me: In particular, a lot of international student visas and scholarship programs insist upon maintaining a B or even A- average to continue. Professors are understandably loathe to condemn a student to having to drop out or return to their home country just because they scored 81% instead of 84% on the final exam. If we really intend to make C the average score, then students shouldn’t lose funding or visas just for scoring a B-. Indeed, I have trouble defending any threshold above outright failing—which is to say, a minimum score of D-. If you pass your classes, that should be good enough to keep your funding.

Yet apparently even this isn’t creating too much upward bias, as students who are 10 IQ points smarter are still getting about the same scores as their forebears. We should be celebrating that our population is getting smarter, but instead we’re panicking over “easy grading”.

But kids these days, am I right?

I’m not sure environmentalists understand what the word “consumption” means to economists.

Feb 25 JDN 2458175

Several times now I’ve heard environmentalists repeat variants of this line: “Capitalist economies depend on consumption; therefore capitalism is incompatible with environmental sustainability.”

A recent example comes from this article on QZ arguing that “conscious consumerism” isn’t viable for protecting the environment:

In short, consumption is the backbone of the American economy—which means individual conscious consumerism is basically bound to fail. “70% of GDP in the US is based on household consumption. So all the systems, the market, the institutions, everything is calibrated to maximize consumption,” Brown told me in a later interview. “The whole marketing industry and advertising invents new needs we didn’t know we had.”

Consumption. You keep using that word… I do not think it means what you think it means.

To be clear, let me say that I basically agree that “conscious consumerism” isn’t good enough. There are a few big things you can do to reduce your carbon footprint, like moving to California (or better yet, Scandinavia), becoming vegetarian, driving a hybrid car (or not driving at all), and not flying on airplanes. Aside from that, your consumer choices are not going to have a large impact. There is a huge amount of greenwashing that goes on—products that present themselves as eco-friendly which really aren’t. And these things by themselves are not enough. A 2012 study by the European Roundtable on Sustainable Consumption and Production found little or no difference in long-run carbon footprint between people who claim to be “green consumers” and people who don’t.

Moreover, there is a strong positive correlation between a country’s GDP and its carbon footprint. The list of countries with the highest carbon emissions looks a lot like the list of countries with the highest GDP.

But there is still substantial variation in the ratio of GDP to carbon emissions. Scandinavia does extremely well, at over $5,000 per ton (as does France, thanks to nuclear energy), while most European countries make about $3,000 per ton, the US is at about $2,000 per ton, and the very most carbon-intensive economies like China, the UAE, and South Africa only make about $1,000 per ton. China produces more carbon emissions per capita than Denmark despite having only one-third the standard of living (at purchasing power parity). Emissions also vary a great deal by states within the US; California’s per-capita emissions are comparable to France’s, while Wyoming’s are worse than the UAE’s.

This brings me to my main point, which is that economists don’t mean the same thing by the word “consumption” that environmentalists do. The environmentalist meaning might be closer to common usage: When something is consumed, we think of it as being destroyed, despoiled, degraded. (It’s even an archaic euphemism for tuberculosis.) So I can see why you would think that if our economy is 70% “consumption” that must make capitalism terrible for the environment: An economy that is 70% destruction, despoliation, and degradation does sound pretty bad.

But when economists use the word “consumption”, what we actually mean is private household expenditure. Our economy is 70% “consumption” in the sense that 70% of the dollars spent in GDP are spent by private individuals as opposed to corporations or the government. Of the $19.7 trillion of US GDP, $13.6 trillion was personal consumption expenditures. That’s actually 69%, but it’s okay to round up to 70%. The rest is made up of $3.4 trillion in government spending, $3.3 trillion in private investment, and a loss of $0.6 trillion from our trade deficit.

There’s no particular connection between private household expenditure and destruction, despoliation, or degradation. In fact, the most destructive form of GDP is obviously military spending, which is not counted as “consumption” in the National Income and Product Accounts but rather as “government expenditure”. Military spending is almost pure waste from an ecological perspective; it consumes mind-boggling amounts of fossil fuels in addition to causing death and destruction. The US military produces almost as much total carbon emissions as the entire country of Denmark.

In fact, the vast majority of private household expenditure in highly-developed countries is in the form of services—over $9.2 trillion in the US. The top four categories for expenditure on services in the US are housing/utilities, healthcare, finance, and food service. I can at least see how housing and utilities would be related to ecological impact—concrete and steel are very carbon-intensive, as is electricity if you’re not using nuclear or renewables. But healthcare, finance, and food service? When environmentalists point to the fact that 70% of our economy is consumption as evidence of the fundamental unsustainability of capitalism, this amounts to asserting that the reason we can’t prevent global warming is that there are so many nurses, accountants, and waiters.

Of course, most people don’t quite grasp what economists mean when we use the word “consumption”, so it makes for a nice talking point for environmentalists. You can conjure images of degradation and destruction while citing the respected authority of the National Income and Product Accounts. If you were already left-wing otherwise (as most environmentalists are), you can make it seem as though the problem is capitalism itself, the very structure of an economy built upon “consuming” the Earth.

In reality, there is enormous variation between countries in terms of their carbon efficiency, and in fact the most carbon-efficient nations are all those that have the highest degrees of political and economic freedom—which is to say, social democracies. One can debate whether social democracies like Denmark and Sweden are “truly capitalist”, but they definitely have free-market economies with large private sectors. On a global and historical scale, there’s really not that much difference between Denmark and the United States (compare to the USSR, or China, or Burkina Faso, or Medieval Japan, or Classical Rome). And if the US isn’t capitalist, who is?

My advice? Don’t talk about consumption at all. Talk about carbon emissions. Don’t ignore variation in GDP/carbon ratios: If the world copied China, we’d all have a per-capita income of $15,500 and emissions of 7.6 tons of carbon per person per year; but if the world copied Denmark, we’d all have a per-capita income of $51,000 and emissions of 6.8 tons of carbon per person per year. (Granted, even 6.8 is still too high; the targets I’ve seen say we need to be at about 3.0 by 2030. But Denmark has also been trending downward in emissions, so we could copy them on that too.) Reducing our standard of living wouldn’t save us if it meant being like China, and maintaining it wouldn’t hurt us if it meant being like Denmark.

I definitely agree that focusing on consumer choices isn’t good enough. Focus on policy. Carbon taxes, bans on unconventional extraction (e.g. offshore drilling, fracking), heavy investment in solar and nuclear energy, large reforestation projects, research into soil sequestration and ocean seeding. Demand these things from all politicians of all parties at all levels of government always. Don’t take no for an answer—because millions of people will die if we don’t stop climate change.

But I don’t think nurses, accountants, and waiters are the problem—and it doesn’t hurt for people to become vegetarian and buy hybrid cars.

You know what? Let’s repeal Obamacare. Here’s my replacement.

Feb 18 JDN 2458168

By all reasonable measures, Obamacare has been a success. Healthcare costs are down but coverage rates are up. It reduced both the federal deficit and after-tax income inequality.

But Republicans have hated it the whole time, and in particular the individual mandate provision has always been unpopular. Under the Trump administration, the individual mandate has now been repealed.

By itself, this can only be disastrous. It threatens to undermine all the successes of the entire Obamacare system. Without the individual mandate, covering pre-existing conditions means that people can simply wait to get insurance until they need it—at which point it’s not insurance anymore. The risks stop being shared and end up concentrated on whoever gets sick, then we go back to people going bankrupt because they were unlucky enough to get cancer. The individual mandate was vital to making Obamacare work.

But I do actually understand why the individual mandate is unpopular: Nobody likes being forced into buying anything.

John Roberts ruled that the individual mandate was Constitutional on the grounds that it is economically equivalent to a tax. This is absolutely correct, and I applaud his sound reasoning.

That said, the individual mandate is not in fact psychologically equivalent to a tax.

Psychologically, being forced to specifically buy something or face punishment feels a lot more coercive than simply owing a certain amount of money that the government will use to buy something. Roberts is right; economically, these two things are equivalent. The same real goods get purchased, at the same people’s expense; the accounts balance in the same way. But it feels different.

And it would feel different to me too, if I were required to actually shop for that particular avionic component on that Apache helicopter my taxes paid for, or if I had to write a check for that particular section of Highway 405 that my taxes helped maintain. Yes, I know that I give the government a certain amount of money that they spent on salaries for US military personnel; but I’d find it pretty weird if they required me to actually hand over the money in cash to some specific Marine. (On the other hand, this sort of thing might actually give people a more visceral feel for the benefits of taxes, much as microfinance agencies like to show you the faces of particular people as you give them loans, whether or not those people are actually the ones getting your money.)

There’s another reason it feels different as well: We have framed the individual mandate as a penalty, as a loss. Human beings are loss averse; losing $10 feels about twice as bad as not getting $10. That makes the mandate more unpleasant, hence more unpopular.

What could we do instead? Well, obviously, we could implement a single-payer healthcare system like we already have in Medicare, like they have in Canada and the UK, or like they have in Scandinavia (#ScandinaviaIsBetter). And that’s really what we should do.

But since that doesn’t seem to be on the table right now, here’s my compromise proposal. Okay, yes, let’s repeal Obamacare. No more individual mandate. No fines for not having health insurance.

Here’s what we would do instead: You get a bonus refundable tax credit for having health insurance.

We top off the income tax rate to adjust so that revenue ends up the same.

Say goodbye to the “individual mandate” and welcome the “health care bonus rebate”.

Most of you reading this are economically savvy enough to realize that’s the same thing. If I tax you $100, then refund $100 if you have health insurance, that’s completely equivalent to charging you a fine of $100 if you don’t have health insurance.

But it doesn’t feel the same to most people. A fine feels like a punishment, like a loss. It hurts more than a mere foregone bonus, and it contains an element of disapproval and public shame.

Whereas, we forgo refundable tax credits all the time. You’ve probably forgone dozens of refundable tax credits you could have gotten, either because you didn’t know about them or because you realized they weren’t worth it to you.

Now instead of the government punishing you for such a petty crime as not having health insurance, the government is rewarding you for the responsible civic choice of having health insurance. We have replaced a mean, vindictive government with a friendly, supportive government.

Positive reinforcement is more reliable anyway. (Any child psychologist will tell you that while punishment is largely ineffective and corporal punishment is outright counterproductive, reward systems absolutely do work.) Uptake of health insurance should be at least as good as before, but the policy will be much more popular.

It’s a very simple change to make. It could be done in a single tax bill. Economically, it makes no difference at all. But psychologically—and politically—it could make all the difference in the world.