Is it possible that Mark Penn, one of the leading pollsters in America, is a quantitative illiterate?

Penn’s recent Wall Street Journal op-ed interpreted a Technorati poll of bloggers in an obviously absurd manner, claiming that “It takes about 100,000 unique visitors a month to generate an income of $75,000 a year.” In fact, the poll found that those bloggers with more than 100,000 unique visitors made an average of $75,000, but the median income in this group was only $22,000.

Here’s Matthew Yglesias summarizing the problems with Penn’s reasoning:

There are all kinds of problems with the statistical inference Mark Penn reaches in this article but just take a gander at this part of Penn’s response to his critics:

The question of how much traffic it takes to make a living also comes from the Technorati report. We say it takes “about 100,000 unique visitors a month to generate an income of $75,000 a year” and Technorati states those who had 100,000 or more unique visitors the average income is $75,000.

I’m pretty sure you couldn’t get a passing grade on an AP math test making this kind of mistake, much less pass yourself off as a data-crunching expert. Technorati says that the average income of professionals bloggers who have over 100,000 unique visitors per month is $75,000. Penn glosses this as saying that “about 100,000 unique visitors” is enough to earn $75,000 which isn’t even close to being the same thing. The mean earnings of high-traffic bloggers are pretty decent. The median earnings are almost certainly lower. And the earnings of a blogger operating at the low-end of what counts as high-traffic will be lower still.

What’s astonishing is that Penn can charge clients like Hillary Clinton millions of dollars for his insights into polling data (talk about the soft bigotry of low expectations). At some point, the Moneyball-ization of politics will hopefully run people like this out of the profession.

PS This error is so embarrassing/revealing that it would actually be better for Penn if people think he was being intentionally dishonest.