Thursday, October 30, 2008

Stat of the Week: Life Expectancies in Baltimore

"In West Baltimore's impoverished Hollins Market neighborhood, where the average life expectancy is about 63 years...Across town in wealthy Roland Park, where residents live on average to be 83"

It's crazy how great the dispairites are between two locations within a few miles of each other. Infant mortality and violence are probably the biggest contributors to this difference.

Wednesday, October 29, 2008


Like the author of this article I believe abortion should be considered a public health problem.

The hypothesis is based on this research paper in the journal international family planning perspectives which comes to this conclusion:

Abortion rates are no lower overall in areas where abortion is generally restricted by law (and where many abortions are performed under unsafe conditions) than in areas where abortion is legally permitted.

The evidence is there to make the correct public health decision - but instead of promoting sex education and other social measures, the United States wastes their time with whole roe vs. wade (life/choice) argument. I feel both sides of the aisle are looking at this problem in the wrong way - we can have life and choice, but we're too blind to see it.

I can't say I'm a huge fan of that research paper and there are probably some flaws in it. However the issue is - why aren't we talking about roe v. wade instead of just saving lives?

Other people are a lot more passionate about this issue than I am, so maybe someone can enlighten me.

Thursday, October 23, 2008

Evolution and Science in America

Via 2006 National Geographic article:
(blue = believes in evolution, red doesn't)

Selected Quotes:
-"In the U.S., only 14 percent of adults thought that evolution was "definitely true," while about a third firmly rejected the idea. "
-"The researchers cite a 2005 study finding that 78 percent of adults agreed that plants and animals had evolved from other organisms. In the same study, 62 percent also believed that God created humans without any evolutionary development."
-"Fewer than half of American adults can provide a minimal definition of DNA, the authors add. "
My thoughts:
-We need to teach and emphasize genetics much earlier in school (elementary). You can make better inferences about a wide range of topics - history, science, even English when you understand genetics.
-Since a majority of Americans are now required to go to college - all students, particularly liberal arts majors should be required to take some type of biology/genetics class. We need to avoid the hubris of humanities (NYT).
-Get more scientists in public office. According to the above NYT article, there were 218 lawyers, 12 doctors, and 3 biologists in congress in 2005. When 90 percent of our representatives probably have a weak science background, we're probably going to fall behind. See the recent examples of stem cells, climate change, research funding, and bioethics.

Wednesday, October 22, 2008

Stat of the Week

Johns Hopkins study - number of deaths in Iraq

  • Estimated 654,965 additional deaths in Iraq between March 2003 and July 2006

Now over 1 million?

Tuesday, October 21, 2008

Income Distribution

A nice graphic from the economist:

A few things that stand out to me:
-The United States seems the most positively skewed - mean is much greater than the median (5th line)
-There is a significant proportion in the US in the lowest decile compared with other developed countries - Canada, Britain, France...
-US has largest top decile by a fair margin

It would be interesting to see this over statistic over time. I'm guessing that our country has always had a larger range than the other countries. I think it's pretty fair to think that this was constantly changing (under every presidential administration).

Friday, October 17, 2008

What is up with Michigan?

I am bit biased against Michigan because of one of their football teams currently holds a 9 game winning streak against my alma mater (which will hopefully be broken tomorrow).

However, I found this story which we discussed in class especially odd:

The NYT described it like this: "1,000 people who attended a ''rave'' in Michigan and allegedly shared a pacifier dipped in the drug Ecstasy were urged to see a doctor after meningitis was diagnosed in one of them."

-Not only is the pacifier part a bit weird, but supposiedly these teens attended this rave in the middle of a corn field. Really a cornfield?!

Stat of the Week

According to the New Yorker:

"By far the biggest theft problem faced by retailers, however, is employee theft, which accounts for nearly 47% of profit erosion."

(from a 2005 Florida Study - companies lost 1.61 percent of sales to theft or fraud)

I am naive about this subject, but I feel it would be more cost effective on preventing this rather than shoplifters (who make up 33 percent of this sample). You have to consider the negative consequences of attempting to prevent customers from shoplifting like false positives (angry customers leading to lost businness, lawsuits/punitive damges). An earlier version of the study states: "While the average shoplifting incident costs the retailer $212.68, an employee theft averages $1,058.20 per incident."

Investigate Employee Crime more
Replace employees with self-check out machines/robots in the future?

Friday, October 10, 2008

Election Thoughts

- Obama's is about 6 to 7 points up depending on which national tracker you look at. I consider polls have a margin of error of about 4 to 5 points, so Obama is looking pretty good now. That being said there are several reasons that election night will still be interesting.
1. McCain makes national gains in the next 3+ weeks. There are many different scenarios in which this is possible considering where the race was 2 weeks ago. I think Democrats are bit too over confident right now, if that's possible. Assuming McCain does come back there could be some crazy scenarios that I'd like to highlight.

A) Electoral Tie of 269/269. This scenario looked quite possible 2 weeks ago. Obama would have to win all Kerry State except New Hampshire (currently +5.3 obama), and McCain would have to win all Bush States except Colorado (+4.6 obama), Iowa (+10.7 obama), and New Mexico (+6.2 obama) for this to happen. With the recent Obama surge in Ohio, Florida, and Virgina - this doesn't look likely (Sliver has it at a 0.16 probablity). However if McCain made national gains, it does seem possible.

Check out the link above for more, but it looks like it would go to the newly elected house for a vote, and then a senate if as the tiebreaker. One would think this would favor the democrats - but things like popular vote, voter recounts ala florida 2000 (that would be decided by conservative supreme court), need to be taken into account.

B) Maine and Nebraska actually allocate their electoral votes by congressional district
Maine is +7.5 Obama, only 1 point above the national average. The districts in Maine vote approxamiately the same though, so McCain may want to pick one and see if he can turn it red. Nebraska is a deep red state, but has a moderate district that includes Omaha, that Obama could turn blue (but only if it's a blowout - less likely to break a 269-268 ties).

C) Election day surprises?
If it is a good day for McCain - Minnesota and Iowa. These are actually the only two "swing" states that McCain has spent more campaign money than Obama in. Democrats currently believe he's wasting his money, but if McCain mangies to surprise these could be the ones.

If it is a good day for Obama - Indiana, West Virgina, North Carolina, and Georgia. If Obama wins any of these states it will likely be a blow out. Obama's "ground game" has gotten rave reviews, so suprises could happen on these relatively red states because of several different demographic factors.

2. In case of Obama Blowout - Senate races

If Obama wins easily, the analysts will be staying up late on election night trying to figure out if the democrats are able to get a 60 seat filibuster proof majority in the senate. If this happens, it is much more likely that Obama's proposed policies will come to fruition.

Nate Silver currently projects the odds of a 60 seat majority at about 25 percent (see below). The 7 interesting states to watch will be Oregon, Minnesota, North Carolina, Georgia, Kentucky, Mississippi, and Alaska. If results are less favorable for democrats, Colorado and New Hampshire should be a tight race. Basically the Dems need to turn 9 currently republican held senate seats to turn blue. 4 currently look like they are close to a lock, then Dems need 5 of those 7 states I mentioned above for the 60 seat majority. It looks doubtful, but possible.

Wednesday, October 8, 2008

Fat Asians

Obesity is a huge emerging problem that I talked about last month. The most common measurement is BMI, which is flawed in many ways. BMI or Body Mass Index measures your weight compared to your height. It does not take into account muscle or particularly kind of fat (healthly or non-healthly). Muscular men seem to be considered overweight (>25 kg/m^2) or obese (>30 kg/m^2) even appearing very fit and having very low % body fat.

Muscular men are not the only ones mischaracterized by this measure; a 2004 Paper from the Lancet suggests that Asians are at greater risk of obesity related diseases (cardiovascular disease, diabetes) at lower BMIs than Caucasians. Asians appear to have increased subcutaneous and upper body fat that is not captured by the BMIs. These fat measurements can be captured in other ways like body fat percentage....

a study in new york measured the following:
Body Fat % at BMI of 25 kg/m^2
Males: Whites: 19.2, Asians: 23.6
Females: Whites: 34.2 Asians: 36.8

Based on the these finding in others the WHO recommended (pdf) the following:

"For many Asian populations, additional trigger points for
public health action were identified as 23 kg/m2 or higher,
representing increased risk, and 27·5 kg/m2 or higher as
representing high risk. The suggested categories are as
follows: less than 18·5 kg/m2 underweight; 18·5–23 kg/m2
increasing but acceptable risk; 23–27·5 kg/m2 increased
risk; and 27·5 kg/m2 or higher high risk."
To summarize/oversimplify, an overweight Caucasian has a BMI over 25, while an overweight Asian has a BMI over 23. No worries my deceivingly chubby Asian friends, the WHO also mentions that the overweight cutoff varies by Asian population from 22-25. My suggestion for those of all races is to get your body fat percentage measured along with your waist/hip ratio - assuming you need more motivation to eat healthy and exercise (or if you just like numbers). Hopefully in the future the health community can improve on the BMI measure and use a less archaic measurement that is less misleading.

Friday, October 3, 2008

Polling Cell Phones - Missing Obama Votes?

There is an emerging challenge for pollsters in the 2008 election - polling cell phone users.

Cell phone only users are usually those under 30, a group that has been strongly supporting Barack Obama. For their samples most pollsters use a random digit dialer that call only landlines. Therefore they are missing a lot of younger voters in their polling. To make up for this most (respectable) pollsters stratify their sample, making sure they get enough voters in each subgroup including young voters (<30).

The assumption being made with this stratified studies is that the landline user group adequately represents the whole population of cell phone users. Pew Research group recently looked into this problem and found some interesting results...

More specifically.....
"Combining polls it conducted in August and September, Pew found that of people under age 30 with only cell phones, 62 percent were Democrats and 28 percent Republicans. Among landline users the same age, that gap was narrower: 54 percent Democrats, 36 percent GOP.
Similarly, young cell users preferred Democratic presidential candidate Barack Obama over Republican nominee John McCain by 35 percentage points. For young landline users, it was a smaller 13-point Obama edge."
-Baltimore Sun

What could the reason be for this difference? Possibly, cell phone only users are those living in cities and more technologically enabled - two groups that seem to go strong for Obama. In epidemiology speak, age is an effect modifier in this election, and it appears Pew believes "cell phone only use" is a confounder. Nate Silver mentions "Urban voters are about 50 percent more likely to be cellphone-only than rural voters, for instance, and while some pollsters weight by geography, others do not. Thus, you may wind up with a biased sample." So this leads to the possibility that other polling outfits are slightly (unintentionally?) biased towards McCain.

So what can we infer from this?
1. Pollsters are using data from the group of young landline users, who are currently +13 Obama.
2. They are inadvertently excluding from the group that is +35 Obama
3. I have seen data stating about 50 percent or more of adults under 30 are cell phone only users (though less likely to vote than their counterparts).
4. Pollsters weigh younger voters under 30, as about 20 percent of the sample.

So according to Pew, pollsters are inputing the +13 Obama data, when they should be inputing +24 Obama data. Assuming that this data is worth 20 percent of the sample, that equals to a 2.2 percent difference in Obama's favor.

-Polls appear to be under polling Obama by a percentage point or two (estimated 2.2 points) based on this variable alone.

I'm not sure how I missed this. It's a good summary of what polls use cell phone data. Nate comes up with a similar value +2.8 Obama comapring two sets of data.