The cost of marijuana would drop as much as 80% and consumption would rise if Californians vote for Proposition 19, the legalization measure on the November ballot, researchers at Rand’s Drug Policy Research Center have concluded in a detailed analysis of the issue.

The Santa Monica-based, nonprofit research institute predicted the cost of marijuana, which runs between $300 and $450 per ounce, could plunge to about $38 by eliminating the expense of compensating suppliers for the challenges of operating in the black market.

The researchers were not certain how much that decline in price might spur use, but noted that one typical estimate is that a 10% drop in price increases use by about 3%. Other factors, such as the elimination of legal risks, could also increase usage between 5% and 50%.

The report noted that it was impossible to predict tax revenues from the initiative, which leaves that decision up to individual cities and counties. Based on a statewide $50 per ounce tax proposed in a legalization bill introduced by Sen. Tom Ammiano (D-San Francisco), the report said state tax revenues could range from $650 million to $1.49 billion.

“California voters and legislators face considerable uncertainty because it is very difficult to estimate how much more marijuana will be consumed in the state or how the change will affect tax revenues, criminal-justice costs and healthcare costs,” the study concludes. The 54-page report, with 14 pages of footnotes, is called “Altered State?” and was paid for by Rand.