Speaking before an audience composed largely of younger Pittsburghers, the city's two principal mayoral candidates last night agreed on one thing: It's time for change.

The difference was that while Democratic Mayor Luke Ravenstahl said changes are in the works, Republican challenger Mark DeSantis argued that the incumbent's changes are not nearly enough to revitalize the city.

Addressing a crowd of more than 250 at Duquesne University's A.J. Palumbo Center, the two principal candidates squared off in a forum that permitted rebuttal to each other's arguments and highlighted their disparate viewpoints.

They differed on several points, including:

Whether the city is doing enough to attract and keep young people.

Whether the African-American community and other neighborhood residents are adequately involved in plans for development.

Whether nonprofits in the city could be contributing more to relieving the burden on taxpayers.

Whether the city could be operating more efficiently.

And how best to consolidate city-county services.

"People want change," said Mr. DeSantis, 48, a South Side businessman. "They don't want to study change. They want it right now."

"My opponent is painting this bleak picture that nothing is happening in Pittsburgh. That's not the case," Mr. Ravenstahl, 27, responded. "Government has to do more. We've begun that, and we're going to continue to do that under my administration."

The candidates opened the forum at odds over how dire the city's financial struggles are.

"We need to make sure that this city is fiscally sound. Right now, the city is a fiscal basket case," Mr. DeSantis said. "It's going to be decades perhaps before we can pay this [debt] off. ... It's serious enough that we are actually at risk of bankruptcy in the next perhaps two or three years. What we're living in now is the calm before the storm."

"This city will not go bankrupt in the next two or three years," Mr. Ravenstahl shot back. "This city's fund balance, in fact, will grow over the course of the next two or three years. ... We're aware of these issues and we're dealing with them.

"These weren't issues that we created. These are issues that my administration inherited. They didn't develop yesterday, they're not going to be solved tomorrow, but we're putting a plan in place to deal with them long term."

As far as the creation of jobs that will keep young people in Pittsburgh, Mr. Ravenstahl pointed to the city's partnership with local universities to develop high-tech industry.

"We are building 150,000 more square feet of wet-lab high-tech and bio-tech space, so those ideas generated [here] have an opportunity to create a start-up company, to have an opportunity to spin off jobs," he said.

"Building office space doesn't get it done. We have a glut of office space," Mr. DeSantis countered. "In the end, it's not because entrepreneurs can't find office space. It's a deeper issue. It's creating truly fertile soil for companies to start and grow."

Recent controversies, such as the mayor's use of a police SUV, did not come up, though Mr. DeSantis did revisit his contention that a mayor must "lead by example." A mayor's actions, he said, affect the people who work for the city and have an impact on the community.

The evening's most unscripted moment occurred when Mr. DeSantis directly challenged the mayor during a discussion of whether the city could be doing more with less.

"How many of the 200 Act 47 cost-saving recommendations have you implemented?" he asked, referring to suggestions made by the state recovery team created to watch over the city's financial struggles.

Mr. Ravenstahl replied that his administration has submitted two balanced budgets.

"That's not an answer," Mr. DeSantis interrupted, laughing. "Yeah, that's not an answer."

The candidates also were asked whether the city is doing enough to involve neighborhoods and minorities in discussions of development of a casino on the North Shore and a new arena in the Hill District.

"We've done a lousy job of listening," Mr. DeSantis said. "There are groups in this city that are angry because they've been excluded from the process. ... When we spend public dollars, we have to go that extra mile to make sure that everybody is heard all along the way.

The mayor, however, pointed to numerous public and private meetings his administration has had with representatives of the Hill District.

"Thirty years ago, we tore down a neighborhood to build an arena in the Hill District," Mr. Ravenstahl said. "We're going to, now, tear down an arena and rebuild a neighborhood. The Hill District deserves no less, and we're working very hard with them."

The debate, moderated by WQED-TV's Tonia Caruso, was sponsored by the Pittsburgh Urban Magnet Project. Two other candidates -- Libertarian Tony Oliva, 28, of and Ryan Scott, 24, of the Socialist Workers Party -- were each given three minutes of time to speak at the end of the forum.

Mr. Scott used the opportunity to urge Pittsburghers to be more involved on national issues relating to workers. Mr. Oliva promised to bring lower taxes and new ideas to city government.