Parent sex education

A recent XKCD notes that parents may need to teach their parents a lot more about sex now that there are internet popup ads. While it's a funny exaggeration of the situation and it seems to be a new situation, it does illustrate the age-old truth that kids always know more than adults think, making it clear that all the time discussing whether to teach contraception in schools is a waste. A study that I did found that most Southern Baptists surveyed in church Sunday School learn about birth control and STD prevention from their schools and from their peers. Take away the schools, and you are left with peers. And internet pop-up ads.

Quantitative work is not mysterious

Some are impressed by quantitative skills. Those of us who were math and physics majors (or in my case, both) are more realistic. Monday's xkcd gives a secret trick in the mouse-over box that pops up that all math and physics majors learn. For those who haven't figured it out, I'm glad that there's a comic strip to reveal the secret.

Also, a few weeks ago, there was a good xkcd about the attitude of some science types towards about interdisciplinary work.

Another area of broad agreement: adults aren't sexualized enough

Camile Paglia says that upper middle class adult culture isn't sexualized enough, which is the same point that many conservative religious movements do. Femininity has been devalued, different roles for men and women has taken out the mystery and magic of relationships, we oversexualize young people and undersexualize adults. Young people are having sex before marriage, and older people are not marrying or not having sex in marriage. These points appear in many evangelical Christian, Catholic, and Orthodox Jewish assessments of culture, and in dating books from across the spectrum. (An example of the latter: Rachel Greenwald, a secular Jew who did a qualitative study of 1000 men about their dating histories, found in her study that one reason that men cite for not continuing a relationship past early dates is that the women dress and behave on dates in the same way as they do in the office.)

We can keep in mind that every model is wrong, but some models are useful: these statements are of course oversimplifications and generalizations. But it's really interesting to see a point where some from the left and some from the right can agree, when they would agree on so little else.

Something we can all agree on: not sexualizing little girls

USC researchers have released a report on the role of women and girls on children's TV. The research finds that females are underrepresented, portrayed as primarily interested in appearance and romance, and that characters are sexualized. I was shocked to see how two children's TV characters were made over as sexualized. Both characters were originally little girls. Now they look older, thinner, show more skin, and Rainbow Brite especially looks like jail bait.

The right and left wings of the sex education debate don't agree on much, but they do agree that reducing women and girls to sexual and romantic roles is distasteful and inappropriate. I hope that all can find some constructive action to counter these disturbing trends.

Anecdote vs. data: soda taxes

I'm constantly amazed how many people doubt that tobacco taxes and soda taxes work, even people who are educated and listen to empirical research in other parts of their lives. The reasoning seems to be that because they don't feel particularly price sensitive --- making purchase/quantity decisions based on goods' prices --- they aren't price sensitive. Likewise, because they have seen people continue to smoke and buy cigarettes at high prices, they believe few people are smoking less or quitting smoking due to tobacco taxes.

Campaign for Tobacco Free Kids put out a new report on this subject, documenting simultaneous decrease in smoking and increase in revenues from tobacco taxes. The economic research on the subject indicates that soda taxes could be similarly effective.

Going the other way, many people don't perceive expensive produce as a barrier to produce consumption. If they choose to buy more expensive produce (e.g., shopping at a more expensive store, only organic/local), they don't see that their decision to buy more expensive produce could decrease their fruit and vegetable consumption. At most levels of income, probably they will buy less if the produce costs more. Certainly they would buy more if it were cheaper: I've noticed that yelp reviews of lower cost produce shops and supermarkets commonly remark that they can get several huge bags of produce for the cost of one bag of produce at their regular store, and that they do get more when they shop at these stores (e.g., this one in Chicago).

People who otherwise listen to economic research and use it to guide decisions and opinions in the rest of their lives, and who believe in things that they can't see like germs, atoms, and molecules, somehow don't believe in price elasticity because they can't see it. I wonder if anyone's researched the impact of belief in price elasticity on economic behavior.

Limits of randomized experiments

I just got back from the Mid-Atlantic Causal Inference Conference, the leading meeting for statisticians who look not just for associations, but for causality. Randomized experiments are the gold standard for causality because randomization ensures that on average, the treatment and comparison groups are similar. Experiments do have limitations, however, that come primarily from their great expense: experiments may need to be small and short duration, weakening the chance that experimenters can see an effect. The study described in this article is a perfect example: 22 autistic children were randomized to a gluten-free, casein-free (GFCF) diet for 18 weeks and then given a "challenge" of these foods about 4 weeks into the trial; by the end of the trial 8 of the subjects had dropped out.

Seemingly, there are hundreds of parents on internet mailing lists and websites putting their children on a GFCF diet. GFCF diet is hard to implement, and it takes weeks or months or practice to get right, and even then an errant crumb can disrupt the progress, and it's unclear how long kids need to be on the diet to see an improvement because determining the starting point is so inexact. A parent can probably remove >90% of gluten and casein from their child's diet starting on day 1, but hunting down the remaining 10% to reach 100% adherence takes a long time. And 99.9998% adherence may be exactly what's required: the FDA definition of gluten-free is 20 ppm. Once the GFCF diet is in place, many parents say that it improves their children. Now a randomized trial that started out with 22 participants and lost 8 of them comes into the news with the headline, "Eliminating Wheat, Milk From Diet Doesn't Help Autistic Kids."

An experiment doesn't have the luxury of trying to refine the diet to make sure that it's being done correctly, or to figure out the length of time the diet needs to continue until there's improvement. An experiment generally determines the treatment in advance rather than trial and error, since trying to get the best result is, to a certain extent, cheating (i.e., risking a spuriously significant result that occurred simply by chance).

A good experiment is an invaluable tool for understanding reality, but a so-so experiment is no better than a qualitative study of people on internet websites.

Chemicals and comparison groups

Current legislation is trying to ban a plastic that has been used for 50 years to line cans, so I decided to look into how much evidence there is that this plastic is dangerous, and whether the potential substitutes for this plastic are safe. The American Council on Science and Health finds little evidence that this plastic is dangerous; they find no proposals for what plastics might substitute, much less any evidence on the alternatives' safety profiles. Their analysis raises very good points and is worth reading.

Just as in statistics, the important question for any risk analysis is "compared to what?" Nothing is dangerous on an absolute level: risks always have to be weighed against their alternatives. When we banned DDT decades ago, it may or may not have had beneficial effects for the eagle population, but malaria has rebounded: going from millions of cases in Sri Lanka to a couple dozen, and then back up to a million cases after the DDT ban. Malaria still affects hundreds of millions of people around the world, many cases that might be prevented if DDT spraying were allowed. The developed world has not had malaria since the 1940s --- perhaps if malaria had rebounded, perhaps we would see pesticides as the life-saving tools that they are --- but we do have the resurgence of bed bugs, even on the Upper East Side, after they had been almost completely eliminated 50 years ago. Maybe the good effects of the DDT ban are worth hundreds of millions of cases of malaria in the developing world and bedbugs in the developed world, but alternatives always need to be considered. The WHO has backed bringing back DDT because it was so useful.

With the current talk of banning BPA, the comparison group is completely missing. By banning a plastic without discussing alternatives and their risks, we risk having worse alternatives or no alternatives.