What do we mean by “obesity”?

Nov 25 JDN 2458448

I thought this topic would be particularly appropriate for the week of Thanksgiving, since as a matter of public ritual, this time every year, we eat too much and don’t get enough exercise.

No doubt you have heard the term “obesity epidemic”: It’s not just used by WebMD or mainstream news; it’s also used by the American Heart Association, the Center for Disease Control, the World Health Organization, and sometimes even published in peer-reviewed journal articles.

This is kind of weird, because the formal meaning of the term “epidemic” clearly does not apply here. I feel uncomfortable going against public health officials in what is clearly their area of expertise rather than my own, but everything I’ve ever read about the official definition of the word “epidemic” requires it to be an infectious disease. You can’t “catch” obesity. Hanging out with people who are obese may slightly raise your risk of obesity, but not in the way that hanging out with people with influenza gives you influenza. It’s not caused by bacteria or viruses. Eating food touched by a fat person won’t cause you to catch the fat. Therefore, whatever else it is, this is not an epidemic. (I guess sometimes we use the term more metaphorically, “an epidemic of bankruptcies” or an “epidemic of video game consumption”; but I feel like the WHO and CDC of all people should be more careful.)

Indeed, before we decide what exactly this is, I think we should first ask ourselves a deeper question: What do we mean by “obesity”?

The standard definition of “obesity” relies upon the body mass index (BMI), a very crude measure that simply takes your body mass and divides by the square of your height. It’s easy to measure, but that’s basically its only redeeming quality.

Anyone who has studied dimensional analysis should immediately see a problem here: That isn’t a unit of density. It’s a unit of… density-length? If you take the exact same individual and scale them up by 10%, their BMI will increase by 10%. Do we really intend to say that simply being larger makes you obese, for the exact same ratios of muscle, fat, and bone?

Because of this, the taller you are, the more likely your BMI is going to register as “obese”, holding constant your actual level of health and fitness. And worldwide, average height has been increasing. This isn’t enough to account for the entire trend in rising BMI, but it reduces it substantially; average height has increased by about 10% since the 1950s, which is enough to raise our average BMI by about 2 points of the 5-point observed increase.

And of course BMI doesn’t say anything about your actual ratios of fat and muscle; all it says is how many total kilograms are in your body. As a result, there is a systematic bias against athletes in the calculation of BMI—and any health measure that is biased against athletes is clearly doing something wrong. All those doctors telling us to exercise more may not realize it, but if we actually took their advice, our BMIs would very likely get higher, not lower—especially for men, especially for strength-building exercise.

It’s also quite clear that our standards for “healthy weight” are distorted by social norms. Feminists have been talking about this for years; most women will never look like supermodels no matter how much weight they lose—and eating disorders are much more dangerous than being even 50 pounds overweight. We’re starting to figure out that similar principles hold for men: A six-pack of abs doesn’t actually mean you’re healthy; it means you are dangerously depleted of fatty acids.

To compensate for this, it seems like the most sensible methodology would be to figure out empirically what sort of weight is most strongly correlated with good health and long lifespan—what BMI maximizes your expected QALY.

You might think that this is what public health officials did when defining what is currently categorized as “normal weight”—but you would be wrong. They used social norms and general intuition, and as a result, our standards for “normal weight” are systematically miscalibrated.

In fact, the empirical evidence is quite clear: The people with the highest expected QALY are those who are classified as “overweight”, with BMI between 25 and 30. Those of “normal weight” (20 to 25) fare slightly worse, followed by those classified as “obese class I” (30 to 35)—but we don’t actually see large effects until either “underweight” (18.5-20) or “obese class II” (35 to 40). And the really severe drops in life and health expectancy don’t happen until “obese class III” (>40); and we see the same severe drops at “very underweight” (<18.5).
With that in mind, consider that the global average BMI increased from 21.7 in men and 21.4 in women in 1975 to 24.2 in men and 24.4 in women in 2014. That is, the world average increased from the low end of “normal weight” which is actually too light, to the high end of “normal weight” which is probably optimal. The global prevalence of “morbid obesity”, the kind that actually has severely detrimental effects on health, is only 0.64% in men and 1.6% in men. Even including “severe obesity”, the kind that has a noticeable but not dramatic effect on health, is only 2.3% in men and 5.0% in women. That’s your epidemic? Reporting often says things like “2/3 of American adults are overweight or obese”; but all that “overweight” proportion should be utterly disregarded, since it is beneficial to health. The actual prevalence of obesity in the US—even including class I obesity which is not very harmful—is less than 40%.

If obesity were the health crisis it were made out to be, we should expect that global life expectancy is decreasing, or at the very least not increasing. On the contrary, it is rapidly increasing: In 1955, global life expectancy was only 55 years, while it is now over 70.

Worldwide, the countries with the highest obesity rates are those with the longest life expectancy, because both of these things are strongly correlated with high levels of economic development. But it may not just be that: Smoking reduces obesity while also reducing lifespan, and a lot of those countries with very high obesity (including the US) have very low rates of smoking.

There’s some evidence that within the set of rich, highly-developed countries, obesity rates are positively correlated with lower life expectancy, but these effects are much smaller than the effects of high development itself. Going from the highest obesity in the world (the US, of course) to the lowest among all highly-developed countries (Japan) requires reducing the obesity rate by 34 percentage points but only increases life expectancy by about 5 years. You’d get the same increase by raising overall economic development from the level of Turkey to the level of Greece, about 10 points on the 100-point HDI scale.

 

Now, am I saying that we should all be 400 pounds? No, there does come a point where excess weight is clearly detrimental to health. But this threshold is considerably higher than you have probably been led to believe. If you are 15 or 20 pounds “overweight” by what our society (or even your doctor!) tells you, you are probably actually at the optimal weight for your body type. If you are 30 or 40 pounds “overweight”, you may want to try to lose some weight, but don’t make yourself suffer to achieve it. Only if you are 50 pounds or more “overweight” should you really be considering drastic action. If you do try to lose weight, be realistic about your goal: Losing 5% to 10% of your initial weight is a roaring success.

There are also reasons to be particularly concerned about obesity and lack of exercise in children, which is why Michelle Obama’s “Let’s Move!” campaign was a good thing.

And yes, exercise more! Don’t do it to try to lose weight (exercise does not actually cause much weight loss). Just do it. Exercise has so many health benefits it’s honestly kind of ridiculous.

But why am I complaining about this, anyway? Even if we cause some people to worry more about eating less than is strictly necessary, what’s the harm in that? At least we’re getting people to exercise, and Thanksgiving was already ruined by politics anyway.

Well, here’s the thing: I don’t think this obesity panic is actually making us any less obese.

The United States is the most obese country in the world—and you can’t so much as call up Facebook or step into a subway car in the US without someone telling you that you’re too fat and you need to lose weight. The people who really are obese and may need medical help losing weight are the ones most likely to be publicly shamed and harassed for their weight—and there’s no evidence that this actually does anything to reduce their weight. People who experience shaming and harassment for their weight are actually less likely to achieve sustained weight loss.

Teenagers—both boys and girls—who are perceived to be “overweight” are at substantially elevated risk of depression and suicide. People who more fully internalize feelings of shame about their weight have higher blood pressure and higher triglicerides, though once you control for other factors the effect is not huge. There’s even evidence that fat shaming by medical professionals leads to worse treatment outcomes among obese patients.

If we want to actually reduce obesity—and this makes sense, at least for the upper-tail obesity of BMI above 35—then we should be looking at what sort of interventions are actually effective at doing that. Medicine has an important role to play of course, but I actually think economics might be stronger here (though I suppose I would, wouldn’t I?).

Number 1: Stop subsidizing meat and feed grains. There is now quite clear evidence that direct and indirect government subsidies for meat production are a contributing factor in our high fat consumption and thus high obesity rate, though obviously other factors matter too. If you’re worried about farmers, subsidize vegetables instead, or pay for active labor market programs that will train those farmers to work in new industries. This thing we do where we try to save the job instead of the worker is fundamentally idiotic and destructive. Jobs are supposed to be destroyed; that’s what technological improvement is. If you stop destroying jobs, you will stop economic growth.

Number 2: Restrict advertising of high-sugar, high-fat foods, especially to children. Food advertising is particularly effective, because it draws on such primal impulses, and children are particularly vulnerable (as the APA has publicly reported on, including specifically for food advertising). Corporations like McDonald’s and Kellogg’s know quite well what they’re doing when they advertise high-fat, high-sugar foods to kids and get them into the habit of eating them early.

Number 3: Find policies to promote exercise. Despite its small effects on weight loss, exercise has enormous effects on health. Indeed, the fact that people who successfully lose weight show long-term benefits even if they put the weight back on suggests to me that really what they gained was a habit of exercise. We need to find ways to integrate exercise into our daily lives more. The one big thing that our ancestors did do better than we do is constantly exercise—be it hunting, gathering, or farming. Standing desks and treadmill desks may seem weird, but there is evidence that they actually improve health. Right now they are quite expensive, so most people don’t buy them. If we subsidized them, they would be cheaper; if they were cheaper, more people would buy them; if more people bought them, they would seem less weird. Eventually, it could become normative to walk on a treadmill while you work and sitting might seem weird. Even a quite large subsidy could be worthwhile: say we had to spend $500 per person per year to buy every single adult a treadmill desk each year. That comes to about $80 billion per year, which is less than one fourth what we’re currently spending on diabetes or heart disease, so we’d break even if we simply managed to reduce those two conditions by 13%. Add in all the other benefits for depression, chronic pain, sleep, sexual function, and so on, and the quality of life improvement could be quite substantial.

How do we get rid of gerrymandering?

Nov 18 JDN 2458441

I don’t mean in a technical sense; there is a large literature in political science on better voting mechanisms, and this is basically a solved problem. Proportional representation, algorithmic redistricting, or (my personal favorite) reweighted range voting would eradicate gerrymandering forever.

No, I mean strategically and politically—how do we actually make this happen?

Let’s set aside the Senate. (No, really. Set it aside. Get rid of it. “Take my wife… please.”) The Senate should not exist. It is fundamentally anathema to the most basic principle of democracy, “one person, one vote”; and even its most ardent supporters at the time admitted it had absolutely no principled justification for existing. Smaller states are wildly overrepresented (Wyoming, 580,000 people, gets the same number of Senators as California, 39 million), and non-states are not represented (DC has more people than Wyoming, and Puerto Rico has more people than Iowa). The “Senate popular vote” thus doesn’t really make sense as a concept. But this is not “gerrymandering”, as there is no redistricting process that can be used strategically to tilt voting results in favor of one party or another.

It is in the House of Representatives that gerrymandering is a problem.
North Carolina is a particularly extreme example. Republicans won 50.3% of the popular vote in this year’s House election; North Carolina has 13 seats; so, any reasonable person would think that the Republicans should get 7 of the 13 seats. Under algorithmic redistricting, they would have received 8 of 13 seats. Under proportional representation, they would have received, you guessed it, exactly 7. And under reweighted range voting? Well, that depends on how much people like each party. Assuming that Democrats and Republicans are about equally strong in their preferences, we would also expect the Republicans to win about 7. They in fact received 10 of 13 seats.

Indeed, as FiveThirtyEight found, this is almost the best the Republicans could possibly have done, if they had applied the optimal gerrymandering configuration. There are a couple of districts on the real map that occasionally swing which wouldn’t under the truly optimal gerrymandering; but none of these would flip Democrat more than 20% of the time.

Most states are not as gerrymandered as North Carolina. But there is a pattern you’ll notice among the highly-gerrymandered states.

Alabama is close to optimally gerrymandered for Republicans.

Arkansas is close to optimally gerrymandered for Republicans.

Idaho is close to optimally gerrymandered for Republicans.

Mississippi is close to optimally gerrymandered for Republicans.

As discussed, North Carolina is close to optimally gerrymandered for Republicans.
South Carolina is close to optimally gerrymandered for Republicans.

Texas is close to optimally gerrymandered for Republicans.

Wisconsin is close to optimally gerrymandered for Republicans.

Tennessee is close to optimally gerrymandered for Democrats.

Arizona is close to algorithmic redistricting.

California is close to algorithmic redistricting.

Connecticut is close to algorithmic redistricting.

Michigan is close to algorithmic redistricting.

Missouri is close to algorithmic redistricting.

Ohio is close to algorithmic redistricting.

Oregon is close to algorithmic redistricting.

Illinois is close to algorithmic redistricting, with some bias toward Democrats.

Kentucky is close to algorithmic redistricting, with some bias toward Democrats.

Louisiana is close to algorithmic redistricting, with some bias toward Democrats.

Maryland is close to algorithmic redistricting, with some bias toward Democrats.

Minnesota is close to algorithmic redistricting, with some bias toward Republicans.

New Jersey is close to algorithmic redistricting, with some bias toward Republicans.

Pennsylvania is close to algorithmic redistricting, with some bias toward Republicans.

Colorado is close to proportional representation.

Florida is close to proportional representation.

Iowa is close to proportional representation.

Maine is close to proportional representation.

Nebraska is close to proportional representation.

Nevada is close to proportional representation.

New Hampshire is close to proportional representation.

New Mexico is close to proportional representation.

Washington is close to proportional representation.

Georgia is somewhere between proportional representation and algorithmic redistricting.

Indiana is somewhere between proportional representation and algorithmic redistricting.

New York is somewhere between proportional representation and algorithmic redistricting.

Virginia is somewhere between proportional representation and algorithmic redistricting.

Hawaii is so overwhelmingly Democrat it’s impossible to gerrymander.

Rhode Island is so overwhelmingly Democrat it’s impossible to gerrymander.

Kansas is so overwhelmingly Republican it’s impossible to gerrymander.

Oklahoma is so overwhelmingly Republican it’s impossible to gerrymander.

Utah is so overwhelmingly Republican it’s impossible to gerrymander.

West Virginia is so overwhelmingly Republican it’s impossible to gerrymander.

You may have noticed the pattern. Most states are either close to algorithmic redistricting (14), close to proportional representation (9), or somewhere in between those (4). Of these, 4 are slightly biased toward Democrats and 3 are slightly biased toward Republicans.

6 states are so partisan that gerrymandering isn’t really possible there.

6 states are missing from the FiveThirtyEight analysis; I think they couldn’t get good data on them.

Of the remaining 9 states, 1 is strongly gerrymandered toward Democrats (gaining a whopping 1 seat, by the way), and 8 are strongly gerrymandered toward Republicans.

If we look at the nation as a whole, switching from the current system to proportional representation would increase the number of Democrat seats from 168 to 174 (+6), decrease the number of Republican seats from 195 to 179 (-16), and increase the number of competitive seats from 72 to 82 (+10).

Going to algorithmic redistricting instead would reduce the number of Democrat seats from 168 to 151 (-17), decrease the number of Republican seats from 195 to 180 (-15), and increase the number of competitive seats from 72 to a whopping 104 (+32).

Proportional representation minimizes wasted votes and best represents public opinion (with the possible exception of reweighted range voting, which we can’t really forecast because it uses more expressive information than what polls currently provide). It is thus to be preferred. Relative to the current system, proportional representation would decrease the representation of Republicans relative to Democrats by 24 seats—over 5% of the entire House.

Thus, let us not speak of gerrymandering as a “both sides” sort of problem. There is a very clear pattern here: Gerrymandering systematically favors Republicans.

Yet this does not answer the question I posed: How do we actually fix this?

The answer is going to sound a bit paradoxical: We must motivate voters to vote more so that voters will be better represented.

I have an acquaintance who has complained about this apparently paradoxical assertion: How can we vote to make our votes matter? (He advocates using violence instead.)

But the key thing to understand here is that it isn’t that our votes don’t matter at all—it is merely that they don’t matter enough.

If we were living in an authoritarian regime with sham elections (as some far-left people I’ve spoken to actually seem to believe), then indeed voting would be pointless. You couldn’t vote out Saddam Hussein or Benito Mussolini, even though they both did hold “elections” to make you think you had some voice. At that point, yes, obviously the only remaining choices are revolution or foreign invasion. (It does seem worth noting that both regimes fell by the latter, not the former.)

The US has not fallen that far just yet.

Votes in the US do not count evenly—but they do still count.

We have to work harder than our opponents for the same level of success, but we can still succeed.

Our legs may be shackled to weights, but they are not yet chained to posts in the ground.

Indeed, several states in this very election passed referenda to create independent redistricting commissions, and Democrats have gained at least 32 seats in the House—“at least” because some states are still counting mail-in ballots or undergoing recounts.

The one that has me on the edge of my seat is right here in Orange County, which several outlets (including the New York Times) have made preliminary projections in favor of Mimi Walters (R) but Nate Silver is forecasting higher probability for Katie Porter (D). It says “100% of precincts reporting”, but there are still as many ballots uncounted as there are counted, because California now has almost twice as many voters who vote by mail than in person.

Unfortunately, some of the states that are most highly gerrymandered don’t allow citizen-sponsored ballot initiatives (North Carolina, for instance). This is likely no coincidence. But this still doesn’t make us powerless. If your state is highly gerrymandered, make noise about it. Join or even organize protests. Write letters to legislators. Post on social media. Create memes.
Even most Republican voters don’t believe in gerrymandering. They want to win fair and square. Even if you can’t get them to vote for the candidates you want, reach out to them to get them to complain to their legislators about the injustice of the gerrymandering itself. Appeal to their patriotic values; election manipulation is clearly not what America stands for.

If your state is not highly gerrymandered, think bigger. We should be pushing for a Constitutional amendment implementing either proportional representation or algorithmic redistricting. The majority of states already have reasonably fair districts; if we can get 2/3 of the House and 2/3 of the Senate to agree on such an amendment, we don’t need to win North Carolina or Mississippi.

The sausage of statistics being made

 

Nov 11 JDN 2458434

“Laws, like sausages, cease to inspire respect in proportion as we know how they are made.”

~ John Godfrey Saxe, not Otto von Bismark

Statistics are a bit like laws and sausages. There are a lot of things in statistical practice that don’t align with statistical theory. The most obvious examples are the fact that many results in statistics are asymptotic: they only strictly apply for infinitely large samples, and in any finite sample they will be some sort of approximation (we often don’t even know how good an approximation).

But the problem runs deeper than this: The whole idea of a p-value was originally supposed to be used to assess one single hypothesis that is the only one you test in your entire study.

That’s frankly a ludicrous expectation: Why would you write a whole paper just to test one parameter?

This is why I don’t actually think this so-called multiple comparisons problem is a problem with researchers doing too many hypothesis tests; I think it’s a problem with statisticians being fundamentally unreasonable about what statistics is useful for. We have to do multiple comparisons, so you should be telling us how to do it correctly.

Statisticians have this beautiful pure mathematics that generates all these lovely asymptotic results… and then they stop, as if they were done. But we aren’t dealing with infinite or even “sufficiently large” samples; we need to know what happens when your sample is 100, not when your sample is 10^29. We can’t assume that our variables are independently identically distributed; we don’t know their distribution, and we’re pretty sure they’re going to be somewhat dependent.

Even in an experimental context where we can randomly and independently assign some treatments, we can’t do that with lots of variables that are likely to matter, like age, gender, nationality, or field of study. And applied econometricians are in an even tighter bind; they often can’t randomize anything. They have to rely upon “instrumental variables” that they hope are “close enough to randomized” relative to whatever they want to study.

In practice what we tend to do is… fudge it. We use the formal statistical methods, and then we step back and apply a series of informal norms to see if the result actually makes sense to us. This is why almost no psychologists were actually convinced by Daryl Bem’s precognition experiments, despite his standard experimental methodology and perfect p < 0.05 results; he couldn’t pass any of the informal tests, particularly the most basic one of not violating any known fundamental laws of physics. We knew he had somehow cherry-picked the data, even before looking at it; nothing else was possible.

This is actually part of where the “hierarchy of sciences” notion is useful: One of the norms is that you’re not allowed to break the rules of the sciences above you, but you can break the rules of the sciences below you. So psychology has to obey physics, but physics doesn’t have to obey psychology. I think this is also part of why there’s so much enmity between economists and anthropologists; really we should be on the same level, cognizant of each other’s rules, but economists want to be above anthropologists so we can ignore culture, and anthropologists want to be above economists so they can ignore incentives.

Another informal norm is the “robustness check”, in which the researcher runs a dozen different regressions approaching the same basic question from different angles. “What if we control for this? What if we interact those two variables? What if we use a different instrument?” In terms of statistical theory, this doesn’t actually make a lot of sense; the probability distributions f(y|x) of y conditional on x and f(y|x, z) of y conditional on x and z are not the same thing, and wouldn’t in general be closely tied, depending on the distribution f(x|z) of x conditional on z. But in practice, most real-world phenomena are going to continue to show up even as you run a bunch of different regressions, and so we can be more confident that something is a real phenomenon insofar as that happens. If an effect drops out when you switch out a couple of control variables, it may have been a statistical artifact. But if it keeps appearing no matter what you do to try to make it go away, then it’s probably a real thing.

Because of the powerful career incentives toward publication and the strange obsession among journals with a p-value less than 0.05, another norm has emerged: Don’t actually trust p-values that are close to 0.05. The vast majority of the time, a p-value of 0.047 was the result of publication bias. Now if you see a p-value of 0.001, maybe then you can trust it—but you’re still relying on a lot of assumptions even then. I’ve seen some researchers argue that because of this, we should tighten our standards for publication to something like p < 0.01, but that’s missing the point; what we need to do is stop publishing based on p-values. If you tighten the threshold, you’re just going to get more rejected papers and then the few papers that do get published will now have even smaller p-values that are still utterly meaningless.

These informal norms protect us from the worst outcomes of bad research. But they are almost certainly not optimal. It’s all very vague and informal, and different researchers will often disagree vehemently over whether a given interpretation is valid. What we need are formal methods for solving these problems, so that we can have the objectivity and replicability that formal methods provide. Right now, our existing formal tools simply are not up to that task.

There are some things we may never be able to formalize: If we had a formal algorithm for coming up with good ideas, the AIs would already rule the world, and this would be either Terminator or The Culture depending on whether we designed the AIs correctly. But I think we should at least be able to formalize the basic question of “Is this statement likely to be true?” that is the fundamental motivation behind statistical hypothesis testing.

I think the answer is likely to be in a broad sense Bayesian, but Bayesians still have a lot of work left to do in order to give us really flexible, reliable statistical methods we can actually apply to the messy world of real data. In particular, tell us how to choose priors please! Prior selection is a fundamental make-or-break problem in Bayesian inference that has nonetheless been greatly neglected by most Bayesian statisticians. So, what do we do? We fall back on informal norms: Try maximum likelihood, which is like using a very flat prior. Try a normally-distributed prior. See if you can construct a prior from past data. If all those give the same thing, that’s a “robustness check” (see previous informal norm).

Informal norms are also inherently harder to teach and learn. I’ve seen a lot of other grad students flail wildly at statistics, not because they don’t know what a p-value means (though maybe that’s also sometimes true), but because they don’t really quite grok the informal underpinnings of good statistical inference. This can be very hard to explain to someone: They feel like they followed all the rules correctly, but you are saying their results are wrong, and now you can’t explain why.

In fact, some of the informal norms that are in wide use are clearly detrimental. In economics, norms have emerged that certain types of models are better simply because they are “more standard”, such as the dynamic stochastic general equilibrium models that can basically be fit to everything and have never actually usefully predicted anything. In fact, the best ones just predict what we already knew from Keynesian models. But without a formal norm for testing the validity of models, it’s been “DSGE or GTFO”. At present, it is considered “nonstandard” (read: “bad”) not to assume that your agents are either a single unitary “representative agent” or a continuum of infinitely-many agents—modeling the actual fact of finitely-many agents is just not done. Yet it’s hard for me to imagine any formal criterion that wouldn’t at least give you some points for correctly including the fact that there is more than one but less than infinity people in the world (obviously your model could still be bad in other ways).

I don’t know what these new statistical methods would look like. Maybe it’s as simple as formally justifying some of the norms we already use; maybe it’s as complicated as taking a fundamentally new approach to statistical inference. But we have to start somewhere.

How much should we give?

Nov 4 JDN 2458427

How much should we give of ourselves to others?

I’ve previously struggled with this basic question when it comes to donating money; I have written multiple posts on it now, some philosophical, some empirical, and some purely mathematical.

But the question is broader than this: We don’t simply give money. We also give effort. We also give emotion. Above all, we also give time. How much should we be volunteering? How many protest marches should we join? How many Senators should we call?

It’s easy to convince yourself that you aren’t doing enough. You can always point to some hour when you weren’t doing anything particularly important, and think about all the millions of lives that hang in the balance on issues like poverty and climate change, and then feel a wave of guilt for spending that hour watching Netflix or playing video games instead of doing one more march. This, however, is clearly unhealthy: You won’t actually make yourself into a more effective activist, you’ll just destroy yourself psychologically and become no use to anybody.

I previously argued for a sort of Kantian notion that we should commit to giving our fair share, defined as the amount we would have to give if everyone gave that amount. This is quite appealing, and if I can indeed get anyone to donate 1% of their income as a result, I will be quite glad. (If I can get 100 people to do so, that’s better than I could ever have done myself—a good example of highly cost-effective slacktivism.)

Lately I have come to believe that this is probably inadequate. We know that not everyone will take this advice, which means that by construction it won’t be good enough to actually solve global problems.

This means I must make a slightly greater demand: Define your fair share as the amount you would have to give if everyone among people who are likely to give gave that amount.

Unfortunately, this question is considerably harder. It may not even have a unique answer. The number of people willing to give an amount n is obviously dependent upon the amount x itself, and we are nowhere close to knowing what that function n(x) looks like.

So let me instead put some mathematical constraints on it, by choosing an elasticity. Instead of an elasticity of demand or elasticity of supply, we could call this an elasticity of contribution.

Presumably the elasticity is negative: The more you ask of people, the fewer people you’ll get to contribute.

Suppose that the elasticity is something like -0.5, where contribution is relatively inelastic. This means that if you increase the amount you ask for by 2%, you’ll only decrease the number of contributors by 1%. In that case, you should be like Peter Singer and ask for everything. At that point, you’re basically counting on Bill Gates to save us, because nobody else is giving anything. The total amount contributed n(x) * x is increasing in x.

On the other hand, suppose that elasticity is something like 2, where contribution is relatively elastic. This means that if you increase the amount you ask for by 2%, you will decrease the number of contributors by 4%. In that case, you should ask for very little. You’re asking everyone in the world to give 1% of their income, as I did earlier. The total amount contributed n(x) * x is now decreasing in x.

But there is also a third option: What if the elasticity is exactly -1, unit elastic? Then if you increase the amount you ask for by 2%, you’ll decrease the number of contributors by 2%. Then it doesn’t matter how much you ask for: The total amount contributed n(x) * x is constant.

Of course, there’s no guarantee that the elasticity is constant over all possible choices of x—indeed, it would be quite surprising if it were. A quite likely scenario is that contribution is inelastic for small amounts, then passes through a regime where it is nearly unit elastic, and finally it becomes elastic as you start asking for really large amounts of money.

The simplest way to model that is to just assume that n(x) is linear in x, something like n = N – k x.

There is a parameter N that sets the maximum number of people who will ever donate, and a parameter k that sets how rapidly the number of contributors drops off as the amount asked for increases.

The first-order condition for maximizing n(x) * x is then quite simple: x = N/(2k)

This actually turns out to be the precisely the point at which the elasticity of contribution is -1.

The total amount you can get under that condition is N2/(4k)

Of course, I have no idea what N and k are in real life, so this isn’t terribly helpful. But what I really want to know is whether we should be asking for more money from each person, or asking for less money and trying to get more people on board.

In real life we can sometimes do both: Ask each person to give more than they are presently giving, whatever they are presently giving. (Just be sure to run your slogans by a diverse committee, so you don’t end up with “I’ve upped my standards. Now, up yours!”) But since we’re trying to find a benchmark level to demand of ourselves, let’s ignore that for now.

About 25% of American adults volunteer some of their time, averaging 140 hours of volunteer work per year. This is about 1.6% of all the hours in a year, or 2.4% of all waking hours. Total monetary contributions in the US reached $400 billion for the first time this year; this is about 2.0% of GDP. So the balance between volunteer hours and donations is actually pretty even. It would probably be better to tilt it a bit more toward donations, but it’s really not bad. About 60% of US households made some sort of charitable contribution, though only half of these received the charitable tax deduction.

This suggests to me that the quantity of people who give is probably about as high as it’s going to get—and therefore we need to start talking more about the amount of money. We may be in the inelastic regime, where the way to increase total contributions is to demand more from each individual.

Our goal is to increase the total contribution to poverty eradication by about 1% of GDP in both the US and Europe. So if 60% of people give, and currently total contributions are about 2.0% of GDP, this means that the average contribution is about 3.3% of the contributor’s gross income. Therefore I should tell them to donate 4.3%, right? Not quite; some of them might drop out entirely, and the rest will have to give more to compensate.
Without knowing the exact form of the function n(x), I can’t say precisely what the optimal value is. But it is most likely somewhat larger than 4.3%; 5% would be a nice round number in the right general range. This would raise contributions in the US to 2.6% of GDP, or about $500 billion. That’s a 20% increase over the current level, which is large, but feasible.

Accomplishing a similar increase in Europe would then give us a total of $200 billion per year in additional funds to fight global poverty; this might not quite be enough to end world hunger (depending on which estimate you use), but it would definitely have a large impact.

I asked you before to give 1%. I am afraid I must now ask for more. Set a target of 5%. You don’t have to reach it this year; you can gradually increase your donations each year for several years (I call this “Save More Lives Tomorrow”, after Thaler’s highly successful program “Save More Tomorrow”). This is in some sense more than your fair share; I’m relying on the assumption that half the population won’t actually give anything. But ultimately this isn’t about what’s fair to us. It’s about solving global problems.

Halloween is kind of a weird holiday.

Oct 28 JDN 2458420

I suppose most holidays are weird if you look at them from an outside perspective; but I think Halloween especially so, because we don’t even seem to be clear about what we’re celebrating at this point.

Christmas is ostensibly about the anniversary of the birth of Jesus; New Year’s is about the completion of the year; Thanksgiving is about the founding of the United States and being thankful for what we have; Independence Day is about declaring independence from Great Britain.

But what’s Halloween about, again? Why do we have our children dress up in costumes and go beg candy from our neighbors?

The name comes originally from “All Hallow’s Eve”, the beginning of the three-day Christian holiday Allhallowtide of rememberance for the dead, which has merged in most Latin American countries with the traditional holiday Dia de los Muertos. But most Americans don’t actually celebrate the rest of Allhallowtide; we just do the candy and costume thing on Halloween.

The parts involving costumes and pumpkins actually seem to be drawn from Celtic folk traditions celebrating the ending of harvest season and the coming of the winter months. It’s celebrated so early because, well, in Ireland and Scotland it gets dark and cold pretty early in the year.

One tradition I sort of wish we’d kept from the Celtic festival is that of pouring molten lead into water to watch it rapidly solidify. Those guys really knew how to have a good time. It may have originated as a form of molybdomancy, which I officially declare the word of the day. Fortunately by the power of YouTube, we too can enjoy the excitement of molten lead without the usual fear of third-degree burns. The only divination ritual that we kept as a Halloween activity is the far tamer apple-bobbing.

The trick-or-treating part and especially the costume part originated in the Medieval performance art of mumming, which is also related to the modern concept of mime. Basically, these were traveling performance troupes who went around dressed up as mythological figures, did battle silently, and then bowed and passed their hats around for money. It’s like busking, basically.

The costumes were originally religious or mythological figures, then became supernatural creatures more generally, and nowadays the most popular costumes tend to be superheroes. And since apparently we didn’t want people giving out money to our children, we went for candy instead. Yet I’m sure you could right a really convincing economics paper about why candy is way less efficient, making both the parents giving, the child receiving, and the parents of the child receiving less happy than the same amount of money would (and unlike the similar argument against Christmas presents, I’m actually sort of inclined to agree; it’s not a personal gesture, and what in the world do you need with all that candy?).

So apparently we’re celebrating the end of the harvest, and also mourning the dead, and also being mimes, and also emulating pagan divination rituals, but mainly we’re dressed up like superheroes and begging for candy? Like I said, it’s kind of a weird holiday.

But maybe none of that ultimately matters. The joy of holidays isn’t really in following some ancient ritual whose religious significance is now lost on us; it’s in the togetherness we feel when we manage to all coordinate our activities and do something joyful and out of the ordinary that we don’t have to do by ourselves. I think deep down we all sort of wish we could dress up as superheroes more of the time, but society frowns upon that sort of behavior most of the year; this is our one chance to do it, so we’ll take the chance when we get it.

How to respond to dog whistles

Oct 21 JDN 2458413

Political messaging has grown extremely sophisticated. The dog whistle technique is particularly powerful one: it allows you to say the same thing to two different groups and have them each hear what they wanted to hear. The term comes from the gadget used in training canines, which emits sounds at a frequency which humans can’t hear but dogs can. Similar concepts have been around for a long time, but the word wasn’t used for this specific meaning until the 1990s.

There was once a time when politicians could literally say different things to different groups, but mass media has made that effectively impossible. When Mitt Romney tried to do this, it destroyed his (already weak) campaign. So instead they find ways to convey two different meanings, while saying the same words.

Classic examples of this include “law and order” and “states’ rights”, which have always carried hidden racist connotations, yet on their face sound perfectly reasonable. “Family values” is another one.

Trump is particularly inelegant at this; his dog whistles often seem to drop into the audible frequency range, as when he called undocumented immigrants (or possibly gang members?) “animals” and tweeted about “caravans” of immigrants, and above all when he said “they’re bringing drugs, they’re bringing crime, they’re rapists”. (Frankly, does that even count as a dog whistle?) He’s a little less obvious in his deployment of “globalist” as a probable anti-Semitic slur.

How should we respond to this kind of coded language?

It’s not as simple as you might think. It’s not always easy to tell what is a dog whistle. Someone talking about crime could be trying to insinuate something about minorities… or, they could just be talking about crime. Someone complaining about immigration could be trying to dehumanize immigrants… or, they could just want a change in our border policy. Accusations of “globalism” could be coded anti-Semitism… or they could just be nationalism.
It’s also easy to accuse someone of using dog whistles even if they probably aren’t: It is now commonplace for the right wing to argue that “common-sense gun control” means confiscating all handguns (when it in fact means universal background checks, mandatory safety classes, and perhaps assault weapon bans and magazine limits, all of which are quite popular even among gun owners), or to argue that “safe, legal, and rare” is just a Trojan horse for unrestricted free abortion (when in fact “safe, legal, and rare” is the overwhelming majority view among Americans). Indeed, it’s quite probable that many of the things that the left wing has taken as dog whistles by Trump were actually overreactions—Trump is bigoted, but not especially so by the standards of old White Republican men. The best reasons to want Trump out of office involve his authoritarianism, his corruption, and his incompetence, not his bigotry. Foreign policy and climate change should be issues that overwhelm basically everything else—these are millions of lives on the line—and they are the two issues that Trump gets most decisively wrong.

The fact that it can be difficult to tell which statements are dog-whistles is not a bug but a feature: It provides plausible deniability.

If you can structure your speech so that it will be heard by your base as supporting a strong ideological platform, but when the words are analyzed they will be innocuous enough that no one can directly prove your extremism, you can have your cake and eat it too. Even if journalists go on to point out the dog whistles in your speech, moderates on your side of the fence might not hear the same dog whistles, and then just become convinced that the journalists are overreacting. And they might even be overreacting.

Instead, I think there are two things we need to do, which are distinct but complementary.’

1. Ask for clarification.

Whether you are in a personal conversation with a friend who is spouting talking points, or a journalist interviewing a politician running for office, there will come opportunities where you can directly respond to a potential dog whistle.
Do not accuse them of using a dog whistle—even if you are confident that they are. That will only make them defensive, and make you appear to be the aggressor. Instead, ask them firmly, but calmly:

What exactly do you mean by that statement?”

If they ignore the question or try to evade it, ask again, a little more firmly. If they evade again, ask again. Keep asking until they answer you or literally force you to shut up. Be confident, but calm and poised. Now they look like the aggressor—and above all, they sound like they have something to hide.

Note also that if it turns out not to be a dog whistle, they will likely not be offended by your request and will have a perfectly reasonable clarification. For example:

“What did you mean when you said you’re worried about Muslim immigrants?”

“Well, I mean that Muslim societies often have very regressive norms surrounding gender and LGBT rights, and many Muslim immigrants have difficulty assimilating into our liberal values. I think we need to spend more effort finding ways to integrate Muslims into our community and disabuse them of harmful cultural norms.”

“What did you mean when you said you are worried about law and order?”

“I mean that gang violence in several of our inner cities is really out of control, and we need to be working on both investing more in policing and finding better methods of crime prevention in order to keep these communities safe.”

“What ‘states’ rights’ are you particularly concerned about, Senator?”

“I don’t like that the federal government thinks it can impose laws against marijuana based on an absurdly broad reading of the Interstate Commerce Clause. I don’t think it’s right that legitimate businesses in California and Colorado have to operate entirely in cash because federal regulations won’t let them put their money into banks without fear of having it confiscated.”

You may even find that you still disagree with the clarified statement, but hopefully it can be a reasonable disagreement, rather than a direct conflict over fundamental values.

2. State your own positive case.

This is one you can probably do even if you don’t actually get the opportunity to engage directly with people on the other side.

I was actually surprised to learn this, but apparently the empirical data shows that including messages of social justice in your political platform makes it more popular, even among moderates.
This means that we don’t have to respond to innuendo with innuendo—we can come out and say that we think a given policy is bad because it will hurt women or Black people. Economic populism is good too, but we don’t need to rely entirely upon that.

To be clear, we should not say that the policy is designed to hurt women or Black people—even if we think that is likely to be true—for at least two reasons: First, we can’t actually prove that, except in very rare cases, so it makes our argument inherently more tendentious; and second, it makes our whole mode of argumentation more aggressive and less charitable. We should always at least consider the possibility that our opponent’s intentions are noble, and unless the facts utterly force us to abandon that view it should probably be our working assumption.

This means that we don’t even necessarily have to come out and challenge dog whistles. We just need to make a better positive case ourselves. While they are making vague, ambiguous claims about “cleaning up our cities” and “making America great”, we can lay out explicit policy plans for reducing unemployment, poverty, and carbon emissions.

Hillary Clinton almost did this—but she didn’t do it well enough. She relied too heavily on constituents being willing to read detailed plans on her website, instead of summarizing them in concise, pithy talking points to put in headlines. Her line Because we’re going to put a lot of coal miners and coal companies out of business, right?” was indeed taken out of contextbut she should have pushed harder by making an actual slogan, like “End coal burning—save coal communities.” (I literally came up with that in five minutes. She had hundreds of professional campaign staff working for her and they couldn’t do better?) The media did butcher her statements—but she didn’t correct them by putting slogans on yard signs or giving stump speeches in Appalachia.

Indeed, the news media didn’t do her any favors—they spent literally more time talking about her emails than every actual policy issued combined, and not by a small margin. But we can’t rely on the news media—and we don’t have to, in the age of blogs and social media. Instead of assuming that everyone already agrees with us and we will win because we deserve to, we need to be doing what actually works at conveying our message and making sure that we win by the largest margin possible.

If you really want grad students to have better mental health, remove all the high-stakes checkpoints

Post 260: Oct 14 JDN 2458406

A study was recently published in Nature Biotechnology showing clear evidence of a mental health crisis among graduate students (no, I don’t know why they picked the biotechnology imprint—I guess it wasn’t good enough for Nature proper?). This is only the most recent of several studies showing exceptionally high rates of mental health issues among graduate students.

I’ve seen universities do a lot of public hand-wringing and lip service about this issue—but I haven’t seen any that were seriously willing to do what it takes to actually solve the problem.

I think this fact became clearest to me when I was required to fill out an official “Individual Development Plan” form as a prerequisite for my advancement to candidacy, which included one question about “What are you doing to support your own mental health and work/life balance?”

The irony here is absolutely excruciating, because advancement to candidacy has been overwhelmingly my leading source of mental health stress for at least the last six months. And it is only one of several different high-stakes checkpoints that grad students are expected to complete, always threatened with defunding or outright expulsion from the graduate program if the checkpoint is not met by a certain arbitrary deadline.

The first of these was the qualifying exams. Then comes advancement to candidacy. Then I have to complete and defend a second-year paper, then a third-year paper. Finally I have to complete and defend a dissertation, and then go onto the job market and go through a gauntlet of applications and interviews. I can’t think of any other time in my life when I was under this much academic and career pressure this consistently—even finishing high school and applying to college wasn’t like this.

If universities really wanted to improve my mental health, they would find a way to get rid of all that.

Granted, a single university does not have total control over all this: There are coordination problems between universities regarding qualifying exams, advancement, and dissertation requirements. One university that unilaterally tried to remove all these would rapidly lose prestige, as it would not be regarded as “rigorous” to reduce the pressure on your grad students. But that itself is precisely the problem—we have equated “rigor” with pressuring grad students until they are on the verge of emotional collapse. Universities don’t seem to know how to make graduate school difficult in the ways that would actually encourage excellence in research and teaching; they simply know how to make it difficult in ways that destroy their students psychologically.

The job market is even more complicated; in the current funding environment, it would be prohibitively expensive to open up enough faculty positions to actually accept even half of all graduating PhDs to tenure-track jobs. Probably the best answer here is to refocus graduate programs on supporting employment outside academia, recognizing both that PhD-level skills are valuable in many workplaces and that not every grad student really wants to become a professor.

But there are clearly ways that universities could mitigate these effects, and they don’t seem genuinely interested in doing so. They could remove the advancement exam, for example; you could simply advance to candidacy as a formality when your advisor decides you are ready, never needing to actually perform a high-stakes presentation before a committee—because what the hell does that accomplish anyway? Speaking of advisors, they could have a formalized matching process that starts with interviewing several different professors and being matched to the one that best fits your goals and interests, instead of expecting you to reach out on your own and hope for the best. They could have you write a dissertation, but not perform a “dissertation defense”—because, again, what can they possibly learn from forcing you to present in a high-stakes environment that they couldn’t have learned from reading your paper and talking with you about it over several months?

They could adjust or even remove funding deadlines—especially for international students. Here at UCI at least, once you are accepted to the program, you are ostensibly guaranteed funding for as long as you maintain reasonable academic progress—but then they define “reasonable progress” in such a way that you have to form an advancement committee, fill out forms, write a paper, and present before a committee all by a certain date or your funding is in jeopardy. Residents of California (which includes all US students who successfully established residency after a full year) are given more time if we need it—but international students aren’t. How is that fair?

The unwillingness of universities to take such actions clearly shows that their commitment to improving students’ mental health is paper-thin. They are only willing to help their students improve their work-life balance as long as it doesn’t require changing anything about the graduate program. They will provide us with counseling services and free yoga classes, but they won’t seriously reduce the pressure they put on us at every step of the way.
I understand that universities are concerned about protecting their prestige, but I ask them this: Does this really improve the quality of your research or teaching output? Do you actually graduate better students by selecting only the ones who can survive being emotionally crushed? Do all these arbitrary high-stakes performances actually result in greater advancement of human knowledge?

Or is it perhaps that you yourselves were put through such hazing rituals years ago, and now your cognitive dissonance won’t let you admit that it was all for naught? “This must be worth doing, or else they wouldn’t have put me through so much suffering!” Are you trying to transfer your own psychological pain onto your students, lest you be forced to face it yourself?