Tuesday, April 30, 2013

How to Influence a Senator

What does a member of Congress want? Money? Yes, absolutely. But it's important to remember that members of Congress, aside from the few who are outright corrupt, don't want money for its own sake. They want it as a means to an end, and the end is reelection.

If you assume that politicians act in whatever way will help their chances of reelection, you will almost always be right. This need not be cynical self-interest on their part. Perhaps they're playing a long game, and reason that reelection is a precondition for getting anything done in the future. Or perhaps they convince themselves that that's what they're doing. In any case, you'll rarely go wrong by assuming politicians will choose the course that maximizes their chances of reelection.

This brings us to the defeat of universal background checks in the Senate. Given that support for this proposal was around 90%, how can voting against it possibly help senators' chances of reelection?

We have some evidence on that. Here's one of the Democratic defectors, Heidi Heitkamp of North Dakota:

“I think I always had a reputation as somebody who will listen, somebody who is pretty independent-minded but also believes that at the end of the day, you got to listen to your constituents,” Heitkamp told Politico. “In this office, the calls literally were before the last day at least 7 to 1 against that bill. This was after a series of very extensive ad campaigns done in my state saying call me and tell me to support it."

Then we have Republican Jeff Flake of Arizona. He announced that he would vote for cloture on the background-checks amendment, meaning voting to allow it to come to the floor for a vote. This was in opposition to the NRA position, which was to keep it bottled up forever. You can go to his Facebook page and scroll down to April 10 to read about it. Here are the first ten comments on the screen I was looking at (sorry about the HTML problems):

    Jimmy Young we need you defeat this attack on our 2nd amendment right's if not you don't have to worry about us ever supporting you again we will be supporting your challenger.
    Gordon Jones Vote NO on more gun control, criminals don't follow laws by definition. "Universal background check" will only apply to law abiding citizens, not criminals. 

    Abolish the "Gun free zone" law, it only disarms law abiding people, not madmen intent on mayhem. All celebrities and politicians have armed guards and send their kids to schools with armed security, the average American deserves the same protection.

Jeff -Oliver Madly- Clark You'll never have a chance to even read it.

Joe Hannis Harry Reid cannot be trusted. He has an agenda and will stop at nothing to achieve it. BEWARE.

Tim Musa Thanks for letting us down with that douche McCain. I am in AZ and I vote.'I will be happy to vote against you next time around if you go down this path.
April 16 at 12:18am via mobile · Like · 2

Scott Shepherd Jeff Flake, you are a traitor to the American people. You swore to UPHOLD the unites states constitution, not destroy it. I will remember how you vote when it's my turn to vote.
April 16 at 12:46am via mobile · Like · 4

John Crook I am very disappointed in the fact that I supported you by voting for you. NOT one single notch should be made in the second amendment!! I feel that both you and John Mccain have betrayed us!!
April 16 at 12:57am via mobile · Like · 1

David Fischer another rhino...no more votes for you, you should jump the isle, hell the dems probably wont have you either.

Steve Eacret I did not vote for you to be another of the sheep. I will not make that mistake again...
April 16 at 2:04am via mobile · Like · 3
Jake Box Vote No on s649! Vote No on Manchin-Toomey! Vote No to Amnesty or a path to Citizenship! Secure the Border!

Flake ended up voting for cloture but against the background-checks amendment.

Now, are phone calls and Facebook comments a random sample, and thus representative of constituent opinions? Obviously not. So why pay attention to them?

One possibility is that senators are too dumb to realize that these comments are unrepresentative. Here's Heitkamp:

When asked about polling that has consistently shown upwards of 90 percent of Americans supporting an expansion of background checks on gun purchasers, Heitkamp said she doubted that they really reflected public opinion....

Much more likely, though, senators do know that the comments are unrepresentative. But just as politicians care about money as a means to an end, they care about representing constituent opinion as a means to that same end: reelection.

From the standpoint of reelection, politicians have to worry not only about their constituents' preferences, but also about the intensity of those preferences.  A lot of people will have an opinion on issue A, but most of them will decide whether to vote for a politician based on issues A through H. A minority will be single-issue voters, whose entire voting decision will be based on issue A. On that issue pleasing those people is a lot more important than pleasing most people.

Calls and letters are a pretty good way of identifying those people-- if people are willing to go to that trouble, they may feel intensely enough about it to be single-issue voters. I doubt Heitkamp really thinks that all the polls are wrong, but it's pretty unseemly to say in public, "I don't care what my constituents want; I just care what the fanatical minority wants." Note that Heitkamp was just elected this past November and won't be up for reelection for another five and a half years, but she's already worried about it.

You might say, "There's nothing really wrong with this; legislation should reflect intensity of preferences. People who care a lot about an issue should carry more weight than people who don't much one way or the other." Indeed, this is the point of view of one of the best-known theories of political philosophy, utilitarianism.

But in applying that philosophy here there's a problem, one of the biggest problems with representative democracy. We could call it "threshold effects." There are costs to organizing and lobbying. So people with less at stake may choose not to bother, and so may not get represented at all. Their preferences may be not just weighted less, but ignored altogether. It's the same reason there's a milk-producers' lobby, but no milk-drinkers' lobby.

There is a silver lining, though, for believers in democracy. Apparently, you  don't need huge amounts of money to influence a senator.  If you can get a good phone list organized, you may be able to have a significant impact on policy. Of course, it helps if your phone list is made up of paranoid nut cases, but it's time for normal people to step up.

Note: Sometimes you guess wrong about how much the silent majority cares about an issue, as Jeff Flake has found out, to his cost.

Sunday, April 21, 2013

I Did Not Know That, OB/GYN Edition

Following a link recently, I came across a New York Times article from over a year ago about the morning-after pill. I learned you have one chance in forty of getting pregnant after unprotected sex if you use the morning-after pill, compared to one chance in twenty without. Maybe everybody knew this already,  but once I did a little math, there were a couple of implications that I found startling:

  • The morning-after pill only cuts your chances of becoming pregnant in half, which is not all that reassuring. Half of the people who would have gotten pregnant will get pregnant anyway. 
  • Without the morning-after pill, you would need to have unprotected sex thirteen times to have a fifty percent chance of getting pregnant.
If I were the father of a teenage girl, I'd want her to know the first but not the second.

Friday, April 19, 2013

We're the Worst

A brief rant, consequent to the Senate's vote on the gun bill:

Drawing on their abiding ignorance of the rest of the world, Americans are always ready to believe that we're tops in everything. Now, I'm an American, so I think America is the greatest country in the world. The question is, could I convince someone who is not an American? That's not so easy.

Health? We're number 36 in life expectancy, even though we spend more than any other country (and have reduced disposable income as a result). Infrastructure? Number 23. Education? Number 17.

But what is more disturbing, it has occurred to me recently, is that among the industrialized democracies (a group in which I would not include Russia), the U.S. is probably the least democratic.

Just some questions, to which my answer is "not as far as I know":

  • Is there any other country where redistricting is done solely by partisan politicians?
  • Is there any other country where elections are supervised by partisan politicians?
  • Is there any other country where in one house of the legislature some citizens' votes count sixty times much as others?
  • Is there any other country where lobbyists play as prominent a role as they do here?
  • Is there any other country where some people have to stand in line for five or six hours to vote?
  • Is there any other country whose legislature is as paralyzed as ours, as obsessed with trivia, as lacking in actual debate?
We invented the idea of sovereignty of the people. Now we think we're still ahead of everyone else on democracy. We're not. We're behind. Maybe that's why we're behind in so many other things.

Hip Fractures: How to Be a Social Scientist, Sort Of

I recently was reading a health column by Jane Brody in The New York Times about people taking calcium supplements to prevent osteoporosis. As seems to be invariably true in her columns, Brody here took an anti-supplement position. She has some evidence: supplements don't seem to do any good in healthy women, and may do some harm, though not all the studies agree.

Brody's conclusion: Eat more dairy products.

The one indisputable fact is that the safest and probably the most effective source of calcium for strong bones and overall health is diet, not supplements. But few American adults, and a decreasing proportion of children and teenagers, consume enough dairy foods to get the recommended intakes of this essential mineral.

But I had some doubts. I had, for some reason, recently read this article from a medical journal, arguing that hip fractures (taken as an index of osteoporosis) were more common in countries that consumed more animal protein and less vegetable protein. (There was a theory behind this, something about "endogenous acid production consequent to the metabolism of animal proteins.")

This article hadn't specifically looked at dairy consumption, but had included a list of the 33 countries studied, ordered by incidence of hip fractures. Among the countries with the highest incidence were some that I thought probably had high dairy consumption, such as the Scandinavian countries. (Little-known fact: the Vikings were big dairy farmers.) Also, some countries with a strong cultural aversion to dairy products, such as China, had very low rates of hip fracture.

So I decided to investigate further. I found a source on dairy consumption worldwide. If I were doing this for a journal article, I wouldn't cite  a source that cited the FAO, I would just cite the FAO.  Using data on the country level rather than the individual level is not ideal, but no individual-level data was available. (I've decided to grit my teeth and treat "data" as a singular noun.) There were a few countries for which I couldn't find dairy consumption data, so I ended up with 28.

I then created an Excel spreadsheet and made a scatterplot of the data. (For complicated reasons,* I eventually used the natural logs of all the data, which is easy to do in Excel. That's what the "ln" on the axes means. The results are similar without doing that.) If dairy consumption reduced hip fractures, you'd expect to see the points form a rough line that sloped downward from left to right. Instead, the line slopes upward, meaning that higher dairy consumption is associated with more hip fractures. The correlation between (log of) dairy consumption and hip fractures is a strong +.91. (The chart will get bigger if you click on it.)

This certainly casts doubt on the claim that drinking milk reduces osteoporosis. But we're not done yet. Here's the hard part about doing social science: correlation just shows that two things tend occur together. The actual relation between those two things may be masked by other things. 

In this case, when we look at the countries that have low incidence of hip fractures, we see places like Nigeria, China, and Thailand. Countries at the high end include Sweden, Norway, and Germany. Perhaps it's higher income that leads to osteoporosis, and since people in higher-income countries drink more milk, we see milk consumption and osteoporosis together.

Is there a plausible theory that would explain why higher income could result in more osteoporosis? Yes: it's well-known that weight-bearing exercise reduces the risk of osteoporosis, and it's probable that people in poorer countries do more physical labor than people in rich countries.

So let's get some data on per capita GDP in these countries. We'll go to the CIA to get the information. Sure enough, the correlation between between (log of) income and hip fractures is strongly positive at +0.87,  and the correlation between income and dairy consumption is also strong at at +0.84. So it is possible that what we're seeing as an effect of dairy consumption is just the effect of higher income.

To go further, we must cross the line that separates bad social science from normal social science, and measure the effect of each variable holding the other constant. To do that, we'll use multiple regression, which is available on Excel by activating the Data Analysis pack. Here are the results

Look at the column "Coefficients". (Ignore the row labeled "Intercept.") This measures the effect of that variable on hip fractures. Roughly, the coefficients indicate the percentage increase in hip fractures for a one percent increase in dairy consumption or GDP per capita (hip fractures increase by 0.84% and 0.73%,respectively). But the important point is that both effects are positive, meaning that an increase in either is associated with an increase in hip fractures holding the other constant.

Now go to the column "P-value". Here we are asking the question, "How likely is it that the effect of each variable is real and not just a random fluctuation in the numbers we happened to collect?" The effect is probably real if these numbers are small; conventionally we want them to be .05 or smaller, and if so we say they are "statistically significant." As you can see, when we take account of GDP per capita, dairy consumption is statistically very significant (that second  number in the "P-value" column is .000098, which is really small), even though GDP is also significant.

But is this plausible? Do we have an explanation for why drinking milk should be bad for you?

There's only one explanation I can think of: the claim, in the paper I linked to above, that animal protein causes osteoporosis. Dairy is chock-full of animal protein. Let's see if dairy has an effect when we take account of the consumption of animal and vegetable protein, using the figures from the paper.

As you can see, consumption of animal protein (AP g/day) has a statistically significant effect on incidence of hip fractures, as does per capita GDP. But when we take account of those things, dairy has no statistically discernible effect. We have to be careful in interpreting this, though. It doesn't necessarily mean that consumption of dairy has no effect on incidence of hip fractures, just that it has no independent effect. It probably means that consumption of dairy has an effect through its effect on the level of animal protein consumed. And the effect is a bad one.

So it doesn't seem that Brody is on strong ground in recommending consumption of dairy products to ward off osteoporosis.

One last point: You may ask, what does all this have to do with social science? This is epidemiology. That's not a social science, is it?

Whether it is or not, the problems are the same: dealing with non-identical humans, and having to reach conclusions based, usually, on non-experimental data. Of course, there are a lot of natural sciences where you usually can't do experiments, but that's a subject for another time.