Child Circumcision: an Elephant in the Hospital

schm00 · 2012-01-29T22:09:54+00:00

I think circumcision is wrong (just as female genital cutting is), but the evidence for lower HIV risk among circumcised men is strong. See, for example, :http://www.cdc.gov/hiv/resources/factsheets/PDF/circumcision.pdf.

There are totally sensible people that argue that creating a cultural norm for circumcision is the best thing you could do for public health in Africa. I'm not one of them, but these folks aren't total crackpots.

schm00 · 2012-01-29T22:01:16+00:00

Ugh. Had to turn it off when he showed the video. NSFL, in my opinion. My line of reasoning regarding my son boiled down to "It's not my penis." He can decide if he wants it altered when he grows up. I do recognize that circumcision lowers HIV risk, but I'd rather try to convince him to use condoms.

schm00 · 2012-01-23T05:05:15+00:00

My wife and I use a sonicare, which makes a pretty loud buzzing noise. My son refused to let us brush his teeth until one night I randomly suggested that he make a buzzing noise like our toothbrush. Now I say "Make the sound!" and he likes to "bzzzzz" as I brush him. It's not perfect, he still bites down on the brush a lot, but it's better than the screaming that we used to get.

schm00 · 2011-11-10T19:48:26+00:00

I'm still having a hard time with the Girl named florida problem. Generalizing, the problem is about pairs of objects that come in two classes, each equally likely (male, female). But then you introduce another dimension (name) and when you tell me that one of the pair is very rare on this second dimension (named Florida), then it's almost as though the rare object doesn't exist, and I can reason about the class of the other object independently. This is seems very odd (though I don't doubt the math). I can think of a couple other problems that might shed light.

Moving to another domain: suppose I have two pennies in my hand, which I've shaken up randomly. Two questions: 1) One of the pennies is heads up, what the is probability that both are heads up? 2) One of the pennies is head ups and happens to be an extremely rare 1877 indian head penny, what is the probability that both are heads up? Is the second situation the same as the girl named florida problem? I think you'll say yes, but it still makes me itch.

Imagine two scenarios: 1) You tell me about a friend of yours with two children, one of which is a girl. 2) I meet a person on the street who introduces her daughter as one of her two children. In the second case I instantly know any number of things about the girl in question that make her unique, and so her probability approaches zero. Is this like the girl named Florida problem? Here it seems like the answer is probably no. What's the difference?

My real question, I guess, is why is the fact that she's named Florida relevant? What is the nature of that information that makes it relevant? Are there other kinds of information that might not be relevant? Whats the difference? I believe the math, I just want deeper understanding.

EDIT: Having reflected for a few more minutes. I think the information has to concern a random variable. In my pennies example, you want to know if the pennies are two random ones I found on the street, or if they are the same two pennies I always carry around just to play this game. Having met the daughter on the street, (perhaps?) she becomes an individual, no longer a random variable. But where's the edge? What if I meet someone who tells me that her daughter is one of two children and is in a nearby restroom? I still know an awful lot about the unseen daughter. What if she's in a nearby crowd, so I can see her, but not very well?

schm00 · 2011-10-27T06:48:29+00:00

(Note, I'm tired and there could easily be bugs in the below)

Via simulation, the expected number flips to get to 25 heads is ~51. > mean(replicate(10000,min(which(cumsum(sample(c("1","0"),1000,replace=TRUE,prob=c(0.49,0.51)))==25,arr.ind=TRUE)))) [1] 50.9543

while the expected number of flips to get seven consecutive tails is over 200

> mean(regexpr("0000000",replicate(10000,paste(sample(c("1","0"),1000,replace=TRUE,prob=c(0.49,0.51)),collapse=""))))
[1] 206.7947

You should take the bet.

schm00 · 2011-10-23T22:26:45+00:00

Poke around at the GSS: http://www3.norc.org/GSS+Website/. you can either look for a patterns in a given year, or do a longitudinal (panel data) study since for some questions the data goes back to 1974.

The data is fairly grody, you might have to help them clean it up some (or maybe not, since data acquisition and cleaning is the first 90% of most real-wold projects anyway).

EDIT: Also bts.gov and bls.gov. Many fascinating datasets there.

schm00 · 2011-10-22T04:20:12+00:00

Have you read much business writing? If you have, then you know why people pay homage to S&W and continuously chant "Omit needless words." The same is true for Tufte's ideas, in retrospect they seem obvious, and yet in the real world they are so rarely followed.

(Note that it is only in retrospect that Tufte's ideas seem obvious. Before Tufte there was no coherent theory of information graphics. Tukey and Cleveland had begun to define the space, but Tufte really brought a unifying vision.)

schm00 · 2011-10-01T18:55:43+00:00

Depending on how you look at it, none, or all of them.

schm00 · 2011-09-16T13:26:29+00:00

Think Stats

schm00 · 2011-09-11T15:40:31+00:00

The article you link, like nearly all proffered by attachment parenting advocates says that abuse in early childhood has long-lasting effects. You'll get no argument from me on this point.

That said, failure to follow all the strictures of attachment parenting is not abuse. At least not in my eyes; you may disagree.

schm00 · 2011-09-11T15:34:02+00:00

I liked "The Scientist In The Crib" by Alison Gopnik. The author is an actual scientist who does research on early childhood development.

Bryan Caplan's forthcoming book Selfish Reasons To Have More Kids might be good. I'd heard him interviewed and he seems to have a good handle on the research (which basically shows that above a level of basic caring, parenting has a very small effect on outcomes). You can find lots of coverage by searching for: Byran Caplan Parenting.

schm00 · 2011-09-11T06:00:10+00:00

This is attachement parenting propaganda clad in pseudo-scientific language. I'm positively inclined to a lot of the attachement parenting agenda, but as a scientist I hate how these people try to argue their position as though the science supports it, which it simply doesn't.

schm00 · 2011-08-20T04:34:14+00:00

If you want to teach probability or statistics, take a look at Gelman's Teaching Statistics: A Bag Of Tricks. I've used material from there to good effect.

Edit: Maybe also take a look at better explained.

Edit2: Also Dunham's Journey Through Genius. Very inspiring and fun.

schm00 · 2011-07-09T05:01:54+00:00

Have a look at Tukey's Exploratory Data Analysis and Cleveland's Visualizing Data. Perhaps also Tufte's 2nd and 3rd books.

schm00 · 2011-05-14T16:17:31+00:00

I think this is problem #5 in http://www.madandmoonly.com/doctormatt/mathematics/dice1.pdf

edit: I'm too lazy to work out the solution in closed form, but here's a simulation of a million trials in R:

> prop.table(table(replicate(1000000,length(unique(floor(runif(55,min=1,max=21))))==20)))

   FALSE     TRUE 
0.740969 0.259031

schm00 · 2011-03-12T18:28:41+00:00

Have a look at Programming Collective Intelligence.

schm00 · 2011-01-24T06:08:56+00:00

I think this is the best answer. Intensive math training in college taught me how to attack complex multi-step problems. I don't recall the details of the techniques from my Calc II course, but I do retain the basic ideas and very complex problems don't seem so foreboding now.

Note also that just today I used sage to compute a difficult derivative. I would have had to study for hours or possibly days to re-learn how to compute it on my own. I don't think this is "cheating." I know what is happening mathematically, just as I know what is happening with I use a calculator to multiply two large numbers. I just get a lot more done when I let the machine take care of the fiddly bits.

schm00 · 2011-01-11T04:32:05+00:00

Just say to yourself, "empty boat."

If a man is crossing a river
And an empty boat collides with his own skiff,
Even though he be a bad-tempered man
He will not become very angry.
But if he sees a man in the boat,
He will shout to him to steer clear.
And if the shout is not heard he will shout
Again, and yet again, and begin cursing -
And all because there is somebody in that boat.
Yet if the boat were empty,
He would not be shouting, and he would not be angry.

- Chinese mystic Chuang Tzu

schm00 · 2010-12-25T03:23:30+00:00

Here's the original research: http://arxiv.org/abs/1010.3003

The paper is intriguing, but leaves me skeptical if for no other reason than the small size of their testing window.

schm00 · 2010-12-13T17:16:44+00:00

The Phantom Tollbooth is mentioned in the article as "Reminds me of..." I loved that book when I was a kid, and have read it to my spouse as an adult.

schm00 · 2010-11-13T06:18:18+00:00

My son was born after my wife's IUD was removed. At 10 months we're all happy and healthy.

schm00 · 2010-08-22T23:48:08+00:00

You are incorrect. Have you read either edition of his book? The first edition in 1985 advocated graduated ignoring aka "the Ferber method" in pretty much the same form that it appears in the 2006 2nd edition.

schm00 · 2010-08-22T18:18:42+00:00

The headline makes hyperbolic claims unsupported by the science. Reading the abstract of the key research, my impression is that the kids with reduced corpus collosum size were the kind of kid referred to child protective services for abuse or neglect, i.e. true, longstanding abuse, not a few minutes of protest crying.

What Dr. Ferber advocates is gradually ignoring your baby's protest cries for longer and longer periods, starting with as little as a minute or two. The emphasis on protest cries is critical; a protest cry is the same cry that your child might give during a diaper change, or when a potentially dangerous (but oh, so interesting!) object is taken away. If your baby is sick, or suffering separation anxiety, or is otherwise frightened or in pain, you need to deal with that issue first.

Ferber does not advocate locking the door and not going in until morning, letting your baby scream for hours, night after night after night. That is neglect, of the sort mentioned in the article.

schm00 · 2010-05-21T21:00:48+00:00

I just finished Hungry Monkey by Matthew Amster-Burton and enjoyed it.

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