Faulty Reasoning

I was recently sent this article, which states that baby boomers are getting more STDs now than people of the same age were 10 years ago. There's only one problem. The assumption underlying the article, which reports the number of diagnoses instead of the incidence rate, is that there were the same number of people in the age groups in question during both years. But was that actually the case? Let's do a bit of investigating.

According to the U.S. census, there were almost 20 million more people in the 45-64 year old age group in 2010 than there were in 2000. There were also slightly more than 5 million additional adults aged 65 and older. Those statistics reflect an increase in population size of 31 percent and 15 percent respectively. Going back to those absolute numbers from the first article, the proportional rise in the number of STDs did in fact well exceed the change in population size; however, there was no way to know that from the data that was presented.

If we had assumed the population had stayed the same size, the article would have shown a syphilis rate for 45-64 year olds in 2010 that was 2.8 times the rate seen in 2000. With the adjusted population size, that difference was barely 2.2. It's a relatively minor difference in this particular example, but that wouldn't always be the case. There's a good reason why people compare incidence rates and not numbers of cases when they're looking across years and populations. Lots of things can change.

• The Most Common STDs
• What is an incidence rate?

Powered By WizardRSS.com | Full Text RSS Feed | Amazon Affiliate | Android Games | Wordpress Tutorials

Source: http://std.about.com/b/2012/02/10/faulty-reasoning.htm

creams for herpes herpes discharge herpes in throat herpes statistics genital herpes photos