If Pam Joyner, a school principal in Portand, Ore., didn't have an extra pot of money from a districtwide foundation, she is not sure how her school would get by, she said.

Ms. Joyner presides over Lane Middle School, where 85 percent of the students qualify for free or reduced-price lunch because of their low income.

The Portland Public School Foundation collects parent-raised money from across the district, pools it and redistributes it to the neediest schools.

“Here at Lane, we don’t have fund-raisers,” Ms. Joyner said. “Our parents can’t afford that.”

Whether or not parents can pitch in to help pay for their children's public school is becoming increasingly important in determining a school's quality, especially as states and districts continue to cut school budgets across the country.

But with parent fund-raising machines kicking into high gear -- in New York City, the collections by some are in the million-dollar range -- school districts are starting to develop policies to address the resulting issue of fairness.

Schools that serve students from poor families do receive extra public funds to help enhance services, and some principals show extraordinary ingenuity in unearthing foundation and corporate grants. Many charter schools, which are publicly financed in New York, also receive supplementary funds from hedge fund managers and other private sources.

But in New York, all those funding sources only underscore the inequities that remain from neighborhood to neighborhood, school to school. And even some parents who have been instrumental in raising money for their children's schools are concerned about the fairness of it all.

As school districts elsewhere grapple with similar questions, the alternatives have their own limitations. For one, how can someone tell a parent that she can't raise money for her child's school? And, as parents are increasingly asking, is any system a true replacement for public financing?

All these issues, and more, are on the table in Portland, a progressive city of nearly 600,000 people, which confronted them early on by creating the Portland Public School Foundation in 1994.

The fairness issue first emerged in Portland in 1990, when Oregon voters passed Measure 5, which limited property taxes and shifted most financing for schools to the state from the local level. This meant fewer dollars were reaching Portland schools. At public hearings, parent and school board meetings, rallies and marches, parents turned out in droves and strove to figure out the best way to alleviate the impact of the cuts.

One of the most popular ideas was to establish private foundations for individual schools. But the concern was that schools like Lane would then suffer disproportionately.

Parents "were trying to raise money in much bigger ways and we wanted to capture that energy,” said Bobbie Regan, a school board member now and parent of two graduates of Portland public schools. “At the same time, we were realizing that simply allowing schools in wealthier parts of town to benefit without raising up all kids wasn’t fair.”

Parents like Ellen Fortin, a mother of two, grappled with the issue. Ms. Fortin said she found the whole idea of privately financing public schools distasteful. She said it perpetuated inequities and would never be able to compensate for cuts. She said she thought the real solution was state funding, which she has made clear at marches, protests and rallies.

But that kind of change can take years. “In the meantime,” Ms. Fortin said, “I wasn’t prepared to let my child lose out.” She started the foundation that supports her children's former elementary school.

Ms. Regan said the school board realized that keeping middle-class parents involved in public schools would be critical to the continued success of the district, which today has about 47,000 students in 81 schools and is the largest school district in the Pacific Northwest. So a compromise was struck.

Parents could have private foundations for their children's schools. But 30 cents of every dollar raised after the first $10,000 must be passed on to the citywide foundation. From that pool of money, the foundation disburses grants like the one Ms. Joyner counts on each year.

Ms. Fortin said that assuages some of her concerns about the fund-raising gap. She can help her children's schools and contribute to the larger cause at the same time.

But not all are happy to see their fund-raised dollars go elsewhere – particularly at those schools with large, successful foundations.

At Lincoln High School, parents raised $500,000 last year and paid for five teaching positions. That amount could have paid for two more positions, but about $150,000 went to the citywide pool.

Dara Wilk, a parent and the president of Lincoln’s foundation, said she felt the contribution was something to be proud of, “but there are a few that wish it could stay at Lincoln.”

Still, Ms. Wilk said those grumbling about having to give up 30 percent are in the minority. The more common complaint is that it’s not enough.

Kathy Parker had two sons at Lincoln High School in the late 1990s. She gave directly to the citywide foundation instead of to Lincoln’s.

“I never felt like my kid or I should have something at the expense of somebody else,” Ms. Parker said. “My feeling was we have to see the whole city as our kids.”

With 33 school foundations sharing their revenue, the Portland Public School Foundation was able to hand out $965,000 in equity grants to 43 schools across the district this year.

“It’s still not the same” as having well-off parents who can pay for multiple teaching positions, Ms. Joyner, the principal at Lane, said, “but it does create at least a buffer.”

But now, with the onslaught of cuts to public funding, even that buffer is weakening.

“More and more foundation dollars," said Matt Shelby, a district spokesman, "are being used to cover core programs, not extras.”

Ms. Fortin said, “It’s really the kid with his finger in the dike.” Her oldest son now attends Grant High School, which has one of the most diverse student bodies in Portland.

“Our foundation will probably raise $150,000” this year, Ms. Fortin said. She knows it won’t be enough to save all five teaching positions that are on the line. “At the end of the day, we’ll lose three or four teachers. That’s becoming untenable.”

It’s also making her question the entire foundation model.

“I’m starting to feel this wasn’t a good idea,” she said, “It’s a necessary evil, but it’s not the solution.”