How cops calculate street value of drugs

Calculating the so-called street value of drugs is like trying to see into the future with a calculator.

Experienced narcotics cops have a good idea of how drugs are packaged and sold to consumers, and they use that information to guesstimate how much a large shipment of drugs might have been worth down the line if it hadn't been confiscated.

That usually involves dividing kilos and pounds into grams or smaller quantities then multiplying that by the retail value of each bag. Some cops, figuring that the drugs will be "cut" with other substances, use another multiplier. The numbers get real high, real fast.

But it's far from an exact science. It doesn't account for drugs that might have otherwise been consumed, confiscated, or sold at larger quantities — for instance, an "8-ball" of cocaine, or about 3.5 grams — instead of a gram or smaller.

Those variables have the potential to significantly alter the "street value," the number that often winds up in news reports. It bears little resemblance to what the bust cost the drug-distribution system.

"I'm not saying they're wrong, it's just their way of looking at it," David Leff, a narcotics expert who frequently testifies in court, said of police calculations. "It's completely subjective."