Tanya Khovanova's Math Blog

I stumbled upon an article in the Boston Globe (February 29, 2008) titled “Study: Spanking children affects their sex lives as adults.” Here are some quotes:

New research by a University of New Hampshire domestic abuse expert says spanking children affects their sex lives as adults. …[C]hildren who are spanked are more likely as adults to coerce partners to have sex, to have unprotected sex and to have masochistic sex.

The classical method to prove scientifically that spanking affects something is to find many parents of newborn identical twins and persuade them to treat their children the same way, with the exception that they spank one and do not spank the other. The researchers should then compare these twins in their adulthood. Such a project is impossible, as parents are likely to start feeling guilty towards the child they spank, for you can’t separate spanking from the whole package of how parents treat their children.

I decided to study the study. I found a more detailed description of the study in the Concord Monitor. As I suspected, the study was a survey. The survey found a correlation between spanking and “undesirable” sexual behavior. As every statistician knows, correlation doesn’t prove causality.

Here’s another quote from the study: “The best-kept secret in child psychology is that children who were never spanked are among the best behaved.” Did it occur to anyone that the best behaved children do not need spanking?

Could it be that parents who spank their children are tired, impatient and less loving? Could it be that not being loved as a child affects your sexual behaviour as an adult much more than spanking?

Could it be that parents who spank their children are more aggressive in general? Could it be that they pass their aggressive genes to kids and their kids’ aggressive behavior is related not only to upbringing, but to genetics?

Do not get me wrong. I do think that spanking is bad. I am saying that the study doesn’t prove that spanking is affecting anyone’s future sex life.

I am surprised that so many magazines republished the article without thinking. Now all the country is fooled into believing that the easy way to improve their kids’ future sex life is to stop spanking.

Go ahead! Stop spanking. Love your children too.

I tried to enroll on a website recently, but they didn’t allow me to continue without choosing five security questions out of about ten samples they supplied. I started in good faith to do what they asked.

Question: What is your father’s middle name?
Answer: They do not have middle names in Russia; they have something called “otchestvo” and I know seven different ways to spell my father’s.

Question: What is the name of the street on which you were born?
Answer: I am glad it was not Lenin Street, but it was equally bad. Besides, it was renamed and I am not sure which name to choose.

Question: What is the name of your high school?
Answer: Finally, an easy question. In Russia we didn’t have names, but rather numbers for schools. I happily entered 444, and oops — the applet wouldn’t accept numbers.

I couldn’t find five questions that I could answer uniquely and reliably. I felt that the designers of these questions were clueless and disrespectful to other cultures. Then I thought about whether I really wanted some creepy database to know the name of my best friend. No, I didn’t.

Now I have established a file where I put the answers to security questions and I can have all the fun I want with my new biography. I can name my first dog Tom Cruise and have my wedding date be 20 years before I was born. I can name my husband Freedom Of Speech and my city of birth IHateSecurityQuestions. Maybe next time I will switch: Freedom Of Speech will be my dog and Tom Cruise my husband.

If you are lazy like me, you can choose your questions so you have the same answer for everything. This way you do not need to type much into your file. For example, you can name your city, your cat and your best friend George Washington. Or, if you are really lazy, God.

I just read the following in Women’s Health Magazine (March, 2008; page 54): Visa conducted a study of 100,000 fast food restaurant transactions. They found that people who pay with credit cards spend 30% more on food than people who pay cash.

The article concludes with the suggestion to pay cash, so you spend less and lose weight.

My question is: Who is more incompetent, Visa or Women’s Health Magazine?

Perhaps people who do not have credit cards are poorer and more price-conscious; hence, they spend less on food. This might explain the correlation. Here’s another possible explanation: people who are ordering for large groups might prefer to pay with a credit card. Or, maybe stores do not like using credit cards for small transactions, so they encourage people to pay cash for modest orders.

The main rule of statistics is that correlation doesn’t mean causality.

There are several possible answers to my question about incompetence:

• The study wasn’t described correctly in the WH magazine. In this case we can’t say much about the competence of Visa, but WH looks bad.
• The study was described correctly, but the conclusion belongs to WH. In this case Visa is innocent and WH is incompetent.
• The study was described correctly and Visa suggested the conclusions. In this case both are incompetent  — Visa for its conclusions and WH for printing them.

It could well be that paying cash makes you stingier, or at least more price-conscious, but I can’t trust Women’s Health Magazine any more. One thing I know for sure is that math can help you lose weight. Math allows you to differentiate a good study from a dumb study.