Why it's hard to predict demand and supply for marijuana

In 2012, the Washington Office of Financial Management estimated that residents were consuming about 85 metric tons of marijuana. The RAND Corporation now estimates that the number is closer to 175 metric tons. That’s very roughly the difference between about 25 and 50 joints per resident each year. “You need to have a good idea about consumption to make decisions about licensing, how many distributors to allow, how many retail shops,” says Beau Kilmer, the lead researcher on the project. “And it’s important to have this information now, because people will want to know what the world looked like before the stores opened up.”

The Washington State Liquor Control Board is the body responsible for the nuts and bolts of implementing the new law. RAND researched these numbers at their behest and gave them preliminary findings months before the Board finalized rules like limiting the growing canopy, the total amount of square footage in the state that can be used for cultivating cannabis. So the disparity between RAND’s findings and the bureaucrats’ working estimate isn’t as vast as it sounds. Still, Brian Smith, a spokesman for the Board, says that any number is an educated guess at best. “No one knows what this recreational market is going to look like,” he says. “What we’ve been trying to do is establish a legal market where one exists nowhere else in the world. So you base it on the best data you have available to you.”