Two readers have questioned why my column on the amount of money that passes through Baltimore's lucrative drug market didn't include the number of addicts that are in the city. The most common figure has been 50,000 to 65,000 (the city's population is about 630,000). Mayor Sheila Dixon had put it at $10 million along Pennsylvania Avenue alone.

I purposely didn't use the  number. Just as I think it's impossible to calculate the money involved in the drug trade, I don't think we have a good idea of how many people are addicted to drugs here. Back in 2005, Alec MacGillis did a story debunking the number, and I've been wary about using it ever since:

But it is impossible to seriously assess the course of the city's struggle with drugs. And because of that, the city is stuck with a number that has hung around its neck for two decades: 60,000 addicts. That number has been invoked, over and over by countless media and government officials, as shocking shorthand for the city's many ills. It has prevailed, like a broken gauge on a gas tank, through four mayors, a large drop in the city's overall population and major changes in the narcotics trade.

In truth, the number is almost certainly wrong. It was, at best, a hit-or-miss guess to begin with.

The 60,000 estimate has been built on hazy projections and on misinterpretations of researchers' findings, a review of its sources shows. Those who produced it acknowledge its shakiness and say they're uneasy about the way the number is bandied about. Without a prohibitively costly survey, they say, there's no reliable way of keeping score in the fight against addiction.

Yet the figure has been repeated often by the national media, this newspaper, and boosters and critics of the city. The city's Baltimore Believe Web site proclaims: "The epidemic of illegal drugs has turned 60,000 city residents into addicts enslaved by chemical substances." Last month, The New York Times stated that "almost one in 10 people" in the city is addicted to drugs.

The number has at times been used to benefit Baltimore. Public officials and other advocates have wielded the figure to dramatize the city's problems in bids to obtain treatment funding or win approval for initiatives such as needle exchanges.

At the same time, use of the 60,000 figure has helped to propagate a perception of the city as an urban wasteland beyond repair, thereby demoralizing residents and potential visitors, businesses or homebuyers.

That was 2005. And the number still crops up. It should be of no surprise it's cited by people on both ends of a complicated debate -- used to get funding and to show Baltimore's ills.

The article goes on to explain how difficult it is to count the addicts. There are only a few thousand treatment beds, far too few no matter how you do the math and arrests of addicts vary widely depending on the political wind. Alec traced the figure back to a 1986 study done for the state by an outside researcher who found 60,700 people he deemed "dysfunctiional" because of drug use. In 1991, the Baltimore Sun referred to "60,000 drug addicts." In the study, researchers counted people seeking treatment for drug problems and extrapolated the total number from there. As Alec pointed out, it was an educated guess and it's still being used by city officials today.

I think it's time to retire the number for good.

Edward Ericson was the first to ask me about this. He wrote some excellent City Paper articles that tried to put a monetary figure on drug dealing in the city. I thought his pieces were good -- they looked at businesses such as bail bonds and questionable car dealers that make money, or launder it, through the drug trade. It's one approach of many.

Marcia Middleton wrote me this:

What was your purpose? The title is misleading if not absolutely false, and you offer no news content or any attempt at analysis. Did you spend any part of your day trying to figure out what Mayor Dixon meant researching your thesis?  Here's the simple calculation I did: 550 drug addicts on Pennsylvania Avenue spending $50 per day on drugs 365 days per year yields an annual “drug take” of $10,038,000. You think $50 per day is too high, or too low?  Change it.  $20 would be a minimum for any self-respecting addict.  Or make it $100.  You’ve got the range.  Maybe there are more addicts on Pennsylvania Ave, maybe fewer. The police and health departments should have at least an idea of the number.
 
Also in browsing the web you might have also stumbled across the City Paper article “Shadow Players” by Edward Ericson Jr., 28 January 2009. It's worth the read, since Mr. Ericson has basically did all the background for you.  (Note to Mr. Cook: I have been contemplating cancelling my subscription to the Sun because of the complete evisceration of actual journalistic content from the news section.)
 
With an estimated 50,000 addicts living in Baltimore City, we’ve got a $1 billion economy (approximately) that is basically financed by tax dollars, robberies and insurance payouts to crime victims.

I don't doubt her numbers -- $20 to $50 a day sounds about right for an addict to spend on drugs. But I'm not sure where she comes up with 550 addicts on Pennsylvania Avenue. That could be low or could be high. Remember, I said at the end that the mayor probably underestimated the amount. And I don't buy the 50,000-addict number.

I wrote the column because Dixon had cited a number that police say they don't keep or tabulate. That's what made it interesting to me. And I'm not sure whether Dixon meant money that addicts spend or what drug dealers spend or what businesses spend. I find it a fascinating question, but one to which I have yet to find a satisfactory answer.