"Most Admired"—Interpreting Statistics

I recently came across a post online by someone who argued that the stories about Obama's loss of popularity must be bogus, since a poll had shown him to be the most admired man (and Hillary Clinton the most admired woman) in the country. I pointed out in a comment that "most admired" might mean admired by ten percent of the population if nobody else got above nine.

It turns out that I was correct, although the number is a little higher than my example.

The open-ended poll released Monday found 16 percent of people named Obama as the most-admired man, while 15 percent named Clinton as the most-admired woman. Both scores, however, have dropped significantly since 2012.  

In 2012, 30 percent of people named Obama as the most-admired man, while 21 percent named Clinton the most-admired woman. 

(From The Hill)

One implication is that the post's argument was strikingly wrong, since Obama's popularity, by this measure, is only half what it was a year ago. The more interesting point is the risk of arguing from factoids without thinking carefully about what they actually mean.

A Chinese Double Standard

No one thinks of enshrining Hitler nor labels Jewish anger an overreaction when Auschwitz is brought up.

(From a Chinese media source criticizing a visit by the Japanese prime minister to a shrine honoring Japanese war dead)

China does, however, continue to honor Mao, who killed more Chinese than any Japanese war criminal, probably more than all of them put together. Also more people than Hitler killed.

For details, see Rummel's figures on Mao's democide.

More on RSA/NSA

In a recent post, I mentioned the report that RSA accepted a ten million dollar payment from the National Security Agency in exchange for deliberately making a vulnerable pseudorandom number generator the default choice for their encryption software. A recent Wired article by Matt Blaze goes into detail on the technology and its implications. It's worth reading the whole piece—the following is a sketch.

DUAL_EC_DRBG is an algorithm for generating pseudorandom numbers—pseudo because the process is deterministic, so if you know all of the inputs to the  generator you can predict the output. Blaze writes:

One of its parameters, called “Q” in the standard, turns out to have the property that if it is chosen in a certain way, whoever selected it can have a secret backdoor that allows them to reverse the algorithm and discover the seed. (This property of Q appears to have first been noted by Daniel Brown in 2006.) And a fixed value of Q is specified in the standard, with no explanation of how it was selected. That this could provide the NSA with an effective backdoor to predict DUAL_EC_DRBG’s output was observed in a talk at the 2007 CRYPTO conference by Dan Shumow and Niels Ferguson of Microsoft.

In other words, the value of Q could have been chosen in a way that, along with additional information, let those who chose it deduce what number came out of the random number generator, hence predict the key the software using it would generate, hence decrypt messages encrypted with that key. The process only works in one direction—knowing the value of Q doesn't let you deduce the information needed to use it as a back door to decrypt. Knowing how Q was generated does.

Which means, assuming the obvious conjectures are correct, that what the NSA was embedding in RSA software was a master key. Using it the NSA could decrypt information encrypted using numbers generated by DUAL_EC_DRBG. Other people could use that master key only if they were able to get from NSA the information on how the value of Q used in the standard had been generated. 

A very clever idea. Assuming Blaze is correct, quite a lot of the cryptographic infrastructure generated during the nine years when DUAL_EC_DRBG was the default algorithm in RSA encryption software is insecure against the NSA. Also  against anyone else who somehow obtains the information on how Q was generated.

I should  add that RSA has denied the charges but offered no explanation of why they made that particular PNG the default in their software and kept it the default long after security professionals had pointed out its weakness. Nor has RSA denied or explained the purported ten million dollar payment from NSA. Their denial amounts to "trust us, we didn't do it."

Sharia: Constitutional (1). Fiqh: Constitutional (2)

Public discussions of traditional Islamic law, by both supporters and critics, routinely refer to the law as Shari'a. As best I can tell, that is a mistake. Islamic law as it was interpreted by legal scholars and applied in the traditional court system is fiqh. Shari'a is what fiqh would be if the scholars always got it right, something they have never claimed to do. Think of it as law in the mind of God.

The same distinction exists in American constitutional law, even though we confusingly use the same word for both concepts. If a lower level court rules a law unconstitutional, it is making a statement not about the Constitution but about the views of the Supreme Court. Roughly speaking, "this law is unconstitutional" is the prediction that, if the case gets to the Supreme Court, the law will be struck down. 

But consider the same question from the standpoint of a Supreme Court justice. His vote is not a prediction of how he and his colleagues will vote, it is a statement about how they should vote. If he ends up in the minority, the implication is not that he is wrong, only that his view failed to prevail. While his vote may, under the principle of stare decisis, be influenced by past votes of past justices, what determines it is his view of what the Constitution says and how it ought to be interpreted.

A constitutional scholar is likely to use "constitutional" in both senses. In some contexts, the question he is interested in is how the Supreme Court can be expected to rule. In others, it is how it ought to rule.

Think of "constitutional" in the Justice's sense as "constitutional (1)," in the lower court's sense as "constitutional (2)." Shari'a in traditional Islamic law corresponds to constitutional (1) in our system. Fiqh corresponds to constitutional (2).

Evaluating Controversial Claims

Someone makes a scientific claim, typically as an argument for some policy. Examples would be current claims with regard to global warming, claims fifty years ago about the consequences of population growth, claims early in the Obama administration about the need for large deficits to bring down unemployment. There are at least four different ways in which an interested observer can decide whether or not to believe the claim.

1. Partisanship. If you support the policy, believe the claim. If you don't, don't. This is probably the most common approach.

2. Evaluate the arguments for yourself. This is  the most entertaining and educational approach but no more reliable than the first—and likely to give the same answer. There is always controversy about the claim among people better equipped to evaluate it than the random observer, although one side or both may try to deny it. In the case of global warming, the relevant claim is not merely that temperatures are going up, or that the reason is human activity, or that they can be expected to go up by enough to cause serious net costs, but all of those plus the additional claim that there are ways of reducing the increase that are worth their cost. To evaluate all of that you need a reasonably expert knowledge of climatology, statistics, ecology, economics, and probably two or three other fields I have not thought of. Since you don't have all that, you end up believing whichever arguments you want to believe.

3. The argument from authority. You try to figure out what the consensus of the people who are experts is or what some authoritative source of information says. An outsider trying to figure out what professionals in a field believe is at risk of overvaluing whatever position has the most support from public sources of information, such as the mass media, or has done the best job of getting its supporters onto the committees of scientific organizations that put out public statements. And even if he could figure it out for one field, that isn't sufficient. Again taking the global warming case, it is not enough to know what the consensus of the climatologists is, even if you can separate the facts from the puffery on that subject. Climatologists are not economists, so  could be correct about the expected temperature increase and wrong about the magnitude or even the sign of its consequences. Economists are not ecologists, so might show the costs they are looking at to be insignificant while missing the effects of climate change on other species. I discussed problems with this approach at greater length in an earlier post.

4. Prediction. Once such a controversy has been going for a while, partisans have a track record. If they have made confident predictions that turned out to be wrong, that is good evidence that they are either dishonest or arguing from an incorrect theory. Figuring out whether the arguments for a theory are right or wrong is much harder than finding out what that theory predicted. Sometimes all the latter takes is  a book or article by its supporters written a few years back.

The clearest case is the population hysteria of the 1960's. Paul Ehrlich's Population Bomb, published in 1968, confidently predicted mass famine in the third world over the next decade, with hundreds of millions of people starving to death. Not only did it not happen, the real world moved in the opposite direction, with calorie consumption per capita in the third world going up, not down. That is very strong evidence that Ehrlich can not be trusted. It is somewhat weaker evidence that the movement of which he was part, whose members generally took him and his arguments seriously, can not be trusted.

Weaker examples apply to my other two cases. Early in Obama's first term, the Administration offered predictions of what the unemployment rate would be without a stimulus and how much lower it would be with the stimulus that the Administration wanted and got. Actual unemployment rates for the next several years were higher with the stimulus than predicted without it. That does not tell us whether the stimulus was a good policy. It is possible, as its supporters argued after the fact, that things were simply worse than they thought. But it is good evidence that predictions made by Administration economists can not be trusted, that either they were deliberately fudging the results or were using models much less reliable than they claimed.

For the case of global warming, we have the IPCC's repeated overpredictions of global temperatures, hurricane rates that are strikingly lower, not strikingly higher, this year than the average, and a number of other predictions to which the real world has failed to conform. Again, that does not show that the underlying argument is wrong. It does show that the people and models that have been generating the mistaken predictions cannot be trusted.

Which is about the most that the interested outside observer can hope to learn.

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P.S. Not surprisingly, a lot of the comments on this post focus on the particular case of global warming rather than the general argument. One commenter provides a link to an article by Chris Landsea on the effect of global warming on the frequency and strength of hurricanes. One conclusion is that global warming by the end of the century might result in a slight increase in the strength of hurricanes and might also result in a substantial decrease in their frequency. 

Another is that the historical record provides no support for the claim that hurricanes have been becoming more frequent or stronger over the past century or so. The reasons that hurricane damage has trended up is that the total value of property in coastal counties has increased. The reason that the number of recorded hurricanes has trended up is probably the large improvement in our ability to detect hurricanes, in particular ones that fail to make land. For details see the article.

Is RSA Liable to Damages for Fraud?

According to a recent news story, the National Security Agency paid RSA, a major provider of encryption software, ten million dollars to promote a version of its software which the NSA could crack. Assuming the story is true, it would seem to put RSA at risk of being sued for deliberately selling its customers a product it knew to be defective.

"But several (RSA employees) said that RSA also was misled by government officials, who portrayed the formula as a secure technological advance."

It is hard to see why NSA would have to pay RSA to use more secure technology, hence equally hard to believe the claim.

It should also put RSA at risk of prosecution for criminal fraud, fraud being both a crime and a tort. But not much risk, since criminal prosecution is controlled by the government, the same organization a different branch of which, assuming the story is correct, bribed RSA to sell a deliberately crippled product.

Science Has Almost Caught Up with Science Fiction

Beyond This Horizon, an early Heinlein novel, describes a technology for what I like to describe as libertarian eugenics, a way in which a couple can choose, among the children they could have, which one they do have. The central trick is a way of separately analyzing the genes of sperm and egg before combining them.

The obvious problem is how to analyze a cell without damaging it. Heinlein's ingenious solution takes advantage of the fact that egg and sperm each contain half of the full set of genes of the cell from which it is derived—and the process that produces an egg or sperm also produces other bodies with the rest of genes. Analyse an ordinary cell, analyse the extra body, subtract, and you now know what genes are in egg or sperm.

According to a news story published yesterday, someone is finally attempting a version of Heinlein's idea, looking at the polar body that contains the genes that are not in the egg in order to deduce the genes that are. At least, that is what the story seems to be describing, although there are not enough to details to be certain.

Heinlein published the novel, and the idea, in 1942.