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July 31st, 2008 (Permalink)

Headline

House Approves Sweeping Effort to Help Housing

The windows could use washing, too.

July 30th, 2008 (Permalink)

Dueling Polls: Gallup vs. Gallup

A couple of poll-watching items:

  • The latest Gallup/USA Today (USAT) poll has something for everyone: Obama leads by three percentage points―47% to 44%―while McCain leads by four―49% to 45%. How is this possible? For one thing, these are results for two different subgroups: registered voters and "likely" voters, respectively. So, it isn't inconsistent nor necessarily surprising that the two groups should give differing results. Moreover, the margin of error (MoE) for both results is ±4 percentage points, so neither result is statistically significant. Thus, the difference between the two groups could easily be due to random sampling error.

    A more serious discrepancy seems to be that between the USAT poll and Gallup's tracking poll, which showed Obama's lead among registered voters as 8 percentage points for the same time period―48% to 40%―with a MoE of ±2 percentage points. However, if you compare the result for each candidate, rather than comparing the difference between the candidates, the discrepancy disappears: The USAT poll has Obama at 47% while the tracking poll puts him at 48%, which is an insignificant difference, even using the smaller MoE of the tracking poll. USAT shows McCain at 44% and the tracking poll has him with 40%, but the 4 percentage point MoE for USAT means that McCain's support could be as low as that for the tracking poll. So, even this difference could be the result of sampling error.

  • Pollster has a worthwhile article on why the current presidential race is not a "statistical dead heat", as some say:
    …Obama has consistently led in national polls over the past two months. In fact, according to national poll results…Obama had been tied or ahead in 50 consecutive national polls through Sunday. Sure, many polls may show Obama holding a lead within the statistical margin of error, but if Obama and McCain were actually tied, we'd expect as many polls showing McCain ahead as show Obama ahead.

    Read the whole thing.

Sources:

Resource: Dueling Polls, 6/26/2008

July 27th, 2008 (Permalink)

LSAT Logic Puzzle 5

Here's an example of a type of question from the "Logical Reasoning" portion of the LSAT:

If Lucy studied harder for the LSAT, she would have greater self-confidence. As a result, she would have better self-esteem, and would eventually be glad that she worked harder. In addition, her outlook on law school would improve. Therefore, Lucy's confidence will increase if she devotes herself to more intense study for the LSAT.

Which of the following passages uses reasoning most similar in form to the one above?

  1. If you wish to know the future, study the past. What has happened is our only guide to what will happen. Therefore, historians, who look to the past, are most likely to be able to predict the future.
  2. Students who plan to take the LSAT would benefit from tutoring, because they can learn test-taking strategies from those who have already taken it. Moreover, the benefits of tutoring will extend to law school as well. Therefore, students who intend to become lawyers should hire a tutor.
  3. If voters study the candidates' records, they will discover which is the best man for the job. I have more experience than my opponent, and my record will show that I have voted to lower taxes when my opponent voted to raise them. So, if people make an informed decision before they enter the voting booth, they will vote for me.
  4. If the internet had more educational sites, parents would approve of their children spending more time online. Parents would recommend sites to their kids, and would be less afraid to allow them to use the web alone. Eventually, their opinion of the internet would improve. So, parents would accept their kids using the internet if there were more educational websites.
  5. We should pay more attention to the effects of global warming. Not only will sea levels rise and coastlines be flooded, but hurricanes will become more numerous and powerful. Clearly, the President should appoint a special global warming "czar".

Bonus: Identify the fallacy committed by both passages.

Answers

Source: Kaplan LSAT (1999-2000 Edition), p. 168. The puzzle is adapted from question 18.

Previous Puzzles: 1, 2, 3, 4

July 24th, 2008 (Permalink)

Check it Out

Benjamin Radford, who writes a "Bad Science" column for Live Science, has an article on a misleading study of teen date violence. It sounds like a typical example of advocacy research:

There's also the problem of definitions. The study includes being called names or being put down as abuse. By this definition, if anyone you have been involved with has ever put you down or criticized you, you were in an abusive relationship. With such a broad definition, the high abuse rates found are hardly "shocking."

The use of low redefinitions to generate "shocking" statistics is common to studies which are sponsored by advocate groups.

Source: Benjamin Radford, "Alarming Study on Teen Dating Violence Is Flawed", Live Science, 7/24/2008

July 19th, 2008 (Permalink)

"A" v. "The"

A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.―Second Amendment to the United States Constitution

Does the reference to "the right of the people to keep and bear Arms" imply that such a right is "antecedent" to the amendment? Does the use of the word "the", instead of "a", mean that the right to keep and bear arms is a "natural" right that the amendment is enacted to protect, rather than create?

Suppose that I say: "I see a dog in the backyard. The dog in the backyard is black." In the first sentence, "a" occurs, whereas in the second sentence "the" occurs. The first, "a"-occurrence, is the "antecedent" of the second, "the"-occurrence, that is, the second sentence refers back to the dog introduced by "a" in the first sentence. However, if we compare this to the second amendment, there is no antecedent in the constitution itself.

In grammar, the words "a" (or "an") and "the" are called the "indefinite article" and the "definite article", respectively. In logic, a noun phrase that begins with "a" is called an "indefinite description", and one that begins with "the" is a "definite description". Take as an example the indefinite description "a dog in the back yard": what does this mean? It is logically equivalent to "some dog in the backyard". "I see a dog in the backyard" means the same as "I see some dog in the backyard". Suppose that, instead, I said: "I see the dog in the backyard". Intuitively, this would mean that I see my dog, or our dog, or that dog that keeps coming into the backyard, that is, a particular dog that is clear in the context. An indefinite description refers to an indefinite thing, whereas a definite description refers to a definite thing.

When a definite description is used, context determines what particular thing is referred to. This context can include an earlier indefinite description as "antecedent", but it need not. If someone simply refers to "the dog", it is likely that they are referring to their dog, or to the dog that they are looking at.

Logically, the thing that separates indefinite from definite descriptions is uniqueness. "A dog is in the back yard" is true as long as at least one dog is in the back yard, and any dog will do. But "the dog is in the back yard" is only true if one specific dog is in the back yard, said dog being determined by context.

So, how does this apply to interpreting the second amendment? The reason why a definite description often refers back to an antecedent indefinite description is that the antecedent supplies the context that picks out the particular thing referred to. In the amendment, there is no antecedent for the definite description to refer back to.

However, some definite descriptions don't need an antecedent, or any other context, to pick out a unique object. For instance, the phrase "the first person to use an umbrella" refers to a unique person even though we don't know who it was.

So, what is the upshot of these considerations for interpreting the second amendment? It's possible that the drafters of the amendment believed that the right to keep and bear arms was a natural right that, therefore, existed prior to the drafting of the amendment. However, I think it more likely that the relevant natural right would be the right to self-defense, which might justify or ground the constitutional right to keep and bear arms.

A better explanation of the use of a definite description to refer to the right is simply that it is unique; in fact, it's not clear what could be meant by more than one such right since, presumably, one is enough. If one right to keep and bear arms doesn't protect you, why would two or more do so? So, I think that it's a mistake to place any great weight upon the use of the word "the" instead of "a" in the amendment, since there is a good reason for the use of the definite article other than the possible pre-existence of the right.

Sources:

July 12th, 2008 (Permalink)

Poll Watch

A new Newsweek poll is out and, unsurprisingly, it shows Obama with a three percentage-point lead over McCain. Recall that last month's poll from the same magazine had Obama with a fifteen point lead (see the Resources below), and was one of two outlier polls showing him with a double-digit lead. All other polls from about the same time period had Obama with a low single-digit lead, and the current poll is now in line with the other polls.

Also unsurprisingly, Newsweek's report spins the poll as showing a big drop in support for Obama, and speculates about various factors that might account for the drop. In all likelihood, Obama's lead is roughly the same as it was during the last poll and there has been no real drop.

At least the article includes the following passage:

Obama's overall decline from the last NEWSWEEK Poll, published June 20, is hard to explain. Many critics questioned whether the Democrat's advantage over McCain was actually as great as the poll suggested, even though a survey taken during a similar time frame by the Los Angeles Times and Bloomberg showed a similarly large margin. Princeton Survey Research Associates, which conducted the poll for NEWSWEEK, says some of the discrepancy between the two most recent polls may be explained by sampling error.

The only other poll mentioned is the other outlier; unmentioned are the half-dozen other polls at about the same time that had contrary results. We may never know what the problem was with these two polls, but PSRA may be right. As I explained in "How to Read a Poll?" (see the Resources below), one in twenty polls can be expected to be in error by greater than its margin of error. During this campaign season, there may be as many as twenty polls in a month or two, so we should expect at least one outlier in that time frame.

This also illustrates a problem with these media-sponsored polls: when a news organization such as Newsweek pays for a poll, they never want to admit that it might be in error. Moreover, they are reluctant to mention the many other polls sponsored by their competitors, especially if those others cast doubt upon their own. Yet, the best way to get a good idea of what's happening is to compare all the recent polls, rather than to concentrate on just one.

Source: Jonathan Darman, "Glow Fading?", Newsweek, 7/11/2008

Resources:


'ABSOLUTELY RIVETING. AN EXTRAORDINARY FILM.'-Patricia Bosworth, VANITY FAIR
July 11th, 2008 (Permalink)

Blurb Watch: Gonzo

The first blurb in the newspaper ad for the new movie Gonzo (see above) isn't the usual contextomy; in fact, I haven't seen the actual review, which doesn't appear to be available on the web. Instead, there's a different problem with this blurb: the quoted review is from Vanity Fair magazine, which is edited by Graydon Carter. Graydon Carter also happens to be the producer of Gonzo. So, instead of quoting out of context, the blurb appeals to misleading authority of the third kind, that is, a reviewer who has a conflict of interest.

Sources:

July 8th, 2008 (Permalink)

New Book

Todd Riniolo, a psychologist, has a book out called When Good Thinking Goes Bad, which has a highly positive blurb from Michael Shermer―hopefully, he isn't quoted out of context. Of course, I'd love to receive a review copy.

July 7th, 2008 (Permalink)

Fallacy Files Book Club: Nudge,
Chapter 2: Resisting Temptation

Optical illusion speed bumps
  • Before getting to the second chapter, here's an update on the previous one, specifically, the use of an optical illusion to slow traffic. I recently saw a CNN television report on the use of an optical illusion designed to make drivers think that there are speed bumps in the road, thus slowing them down. This is a different type of illusion than the one discussed in the book, which involved painting white stripes on the street that grow closer together in order to give drivers the illusion that their cars are speeding up, encouraging them to compensate by braking.

    The fake speed bumps are currently being tested, but CNN's article mentions that there is some reason to think that their effect in slowing traffic may wear off after awhile. As people become used to the illusions, they may ignore them. The illusion persists, that is, the fake bumps still look as if they are protruding from the surface of the road, but drivers learn not to react to it as if it were real.

    Thaler and Sunstein (T&S) don't mention whether the optical illusion they cite in the book suffers from the same diminishing effectiveness. However, the illusion mentioned in the book is used to slow traffic on a sharp turn. For this reason, drivers who become familiar with the illusion are not likely to start ignoring it, since there is a danger to them of doing so worse than getting a ticket.

    So, this raises a new question about the strength of the analogy between cognitive biases and optical illusions: even if biases are persistent in the way that optical illusions are, perhaps the effect of nudges will wear off as people become used to them. For example, those who are chronically late for appointments may try to trick themselves into arriving on time by setting their watch ahead. However, anyone who tries this trick is likely to find that the effect wears off rapidly as one adjusts to the fact that the watch is set ahead.

    Source: "Optical Illusion Helps Create Fake Speed Bumps", CNN, 6/30/2008

  • The second chapter concerns what philosophers call "weakness of the will", that is, succumbing to temptation. T&S give the example of a bowl of nuts (p. 40): knowing that eating the entire bowl will ruin your appetite―as well as being bad for your diet―you may wish not to do so. Yet, if the bowl remains within reach, you may find yourself consuming them all, seemingly against your own will.

    T&S explain temptation as the result of a kind of internal conflict between a "cold", rational part of the brain and a "hot", emotional part. The cold part recognizes that you should not eat too many nuts, but the hot part wants to eat them all. When you're confronted by the bowl of nuts, the emotional part heats up and may gain the upper hand over the cold part, and there go the nuts.

    I have my doubts about this explanation, at least when applied to the nut example: some of T&S's other examples seem better explained by it, for instance, intending to practice "safe sex" but failing to do so in a moment of passion (p. 42). Based on my experience, there are a couple of facts about the nut example not explained by T&S's theory:

    1. It seems possible to succumb to the temptation of the nuts even in a "cold" state of mind, that is, when one is not hungry.
    2. It seems to be harder to resist the temptation from certain types of foods than others: nuts are a good example, but so are potato chips; in contrast, a large slice of cheesecake may be more tempting than nuts but it is easier to resist the temptation.

    How can we explain these facts? I suggest that there is a "slippery slope" phenomenon at work: foods which come in small pieces, such as nuts and chips, tempt you out on to a slippery slope. "I don't want to eat the whole bowl, but one nut won't hurt," you think. So you eat one nut. However, the same piece of reasoning applies again: one more nut won't hurt, and so on. Once we start down this road the only non-arbitrary stopping point is when the bowl is empty. A single large piece of cake may be just as tempting as the nuts, but instead of a slope there is one step followed by a plummet to the bottom.

    In the remainder of the chapter, T&S discuss various strategies that people use to help them resist temptation, including alarm clocks, Christmas savings clubs, and mental accounting. It's not clear to me what role government can or should be expected to play in helping people control themselves, but apparently that will be dealt with in a later chapter.

Previous Installments:

Next Installment:
Chapter 3: Following the Herd

Answer to LSAT Logic Puzzle 5: 4.
Bonus: Both arguments are circular.

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