Bad math makes for poor reporting

I was forwarded a copy of an article from the Dupont Current about the proposed liquor license moratorium for a circular area surrounding U Street.

In it, staff writer Alix Pianin uncritically paraphrases lead NIMBY Joan Sterling, “In her research, Sterling found that the U Street area has the highest concentration of alcohol-licensed establishments in the city.” Much of the debate about Ms. Sterling’s proposal has revolved around this assertion, which is the central argument made by her and her small group of allies.

This is the same claim Sterling made in her moratorium petition, filed on behalf of the Residential Action Coalition and the Shaw Dupont Citizens Alliance, which she leads:

No other area of the city has so many license crammed into such a small area… Georgetown, Dupont Circle East and West, and Adams Morgan Moratorium Zones, also contain far fewer licenses, singly, or combined when calculated on the size of the Zone, than the proposed Historic 14th and U Street Corridor Moratorium Zone.

In another part of the petition, she claims:

This area has the greatest concentration of alcohol licensed establishments in the city and in fact is significantly higher than any other current Moratorium Zone.

Luckily for us, she provides the following information about the zones and we can evaluate the accuracy of the central claim of the entire petition based on her own numbers:

Location (Moratorium Radius) Total Number of Liquor Licenses
Adams Morgan (1400′) 85
Dupont East (600′) 19
Dupont West (600′) 33
Georgetown (1800′) 94
Glover Park (1200′) 21
U Street (1800′) 107

At first glance, these numbers might make the concentration of liquor licenses in the different zones look comparable. A gullible person might think that U Street does, indeed, have the highest concentration of liquor licenses. But once you recall some basic math the error becomes obvious: the formula for the area of a circle is radius squared, multiplied by Pi. The area of the proposed U Street moratorium (with an 1800′ radius) isn’t three times larger than the Dupont moratorium zones (with 600′ radii), it is actually nine times larger.

Using her numbers, the U Street zone has concentration of 1.05 liquor licenses per 100,000 square feet. Adams Morgan has 1.38 (31% higher concentration), Dupont East has 1.68 (60% higher concentration), and Dupont West has 2.92 (a whopping 178% higher concentration).

Ms. Sterling’s assertion that the proposed U Street moratorium area has the highest concentration of liquor licenses in the District is not only inaccurate, but obviously so, and by an enormous margin.

If we’re going to have a reasonable discussion about liquor licenses and development in DC then we need to start from true premises. This debate isn’t about whether or not the DC government should put some limits on the neighborhood in DC with the “highest concentration of liquor licenses.”

This is really about whether or not a small group of disgruntled residents is going to be able to stop a growing neighborhood based simply on their own, inaccurate perceptions of U Street.