A national accounting firm's estimate of slot machine gambling revenue at a Pennsylvania racetrack raises further doubts about Gov. Ed Rendell's prediction that bringing slot machines to the commonwealth will produce $1 billion a year to help fund property tax relief.

From the outset, Rendell's predictions of $1 billion in slots revenues to the state raised doubts. From what some observers and industry experts are saying, it is possible that the governor tossed out a high-ball estimate to help build support for slot machine gambling. Interestingly, some experts also suggest that the state low-balled the value of the limited casino licenses, by pegging the price at $50 million each rather than setting up a competitive bidding process that would maximize the benefit to state taxpayers.

But, until slot machines are actually up and running, all of the different estimates are just that — estimates.

But it does seem as though prospective casino owners have an incentive to inflate their estimates, because it suggests more money going to the state, and in some cases local projects.The recent PricewaterhouseCoopers study, which predicted slot machine revenue at about 50 percent of the figure predicted by the particular slots applicant, would seem to be more reliable because the accounting firm appears to have no vested interest in the results — unlike the prospective casino operator.

Beyond the impact on the revenue earned by The Meadows harness-racing track in Washington County, the PricewaterhouseCooper study raises doubts about statewide gambling revenue predicted by Rendell and other slots supporters.

Even using Rendell's billion-dollar prediction, the trickle-down benefit to the average property tax payer is estimated to be, on average, about $300 a year. To many property owners, that is not a very significant figure. It hardly seems to offset the negatives associated with creating legalized gambling such as opportunities for political graft and influence peddling, as well as crime and the social ills associated with gambling.

The accounting firm's full report on estimated slot machine revenues remains secret because the state's gambling board, officially known as the state Gaming Control Board, refuses to release it. A number of lawmakers are pushing for release of the full report, and state Rep. Tom Gangretti, D-Greensburg, is correct in suggesting that the report should be released voluntarily by the gambling board. And if that does not happen, the legislature should amend the law to force a full release of the findings.

There is no doubt that Pennsylvania has been missing out on gambling revenues as state residents have for years traveled to New Jersey, West Virginia, New York or Connecticut to gamble. But there are serious doubts about the Rendell administration's predicted revenues from state-sponsored slot machine gambling in Pennsylvania.

The consultant's full report should be released so that the public can decide if the predicted revenue to the state is worth the problems associated with expanded gambling.

Seeing the full report would at least make the public better prepared for a significant shortfall in actual slot machine revenues that many critics of the Rendell plan have been predicting.