The Rand study may clarify some of the many uncertainties still surrounding the homeless population.

"Long sentences for serious crimes have intuitive appeal," the Rand study said.

Rand studies notwithstanding, the United States needs to create opportunity, not just satisfy demand.

But even that would achieve a greater reduction in cocaine use, at a fraction of the cost, than prison, the Rand study stated.

"The Rand study is very conclusive on that score."

For those convicted of drug-related crimes in 1981, the average minimum sentence was 5.5 months, the Rand study found.

The 183-page Rand study appears to be the first to examine the cost-effectiveness of mandatory minimum sentences.

David Grissmer, the lead author of the Rand study, believes substantial help from the federal government is essential.

It is no wonder the Rand study was inconclusive, given the restrictions imposed on the limited voucher programs in place.

A good place to begin is suggested by a 1994 RAND study.