As a team of surveyors prepares to prep the Vineyard for the 2010 U.S. census, the dismal economy is adding bite to questions about accurately counting the transient Island population — since census numbers translate into government spending numbers.

The census provides a population snapshot of one day in April. It’s also a federal spending tool which the census bureau says accounts for some $300 billion in federal spending. Using census numbers, the government allocates spending for schools, roads, bridges, hospitals and other essential services.

Yet the bureau has acknowledged that several million ethnic minorities went uncounted in the 2000 census. Another potential for inaccuracy pertains to resort communities: the bureau announced an overcount of 1.3 million people, due primarily to duplicate counts of whites with second homes.

Then there is the overarching problem that an April survey cannot factor in the huge population bump the Island experiences each summer.

“We’re getting money as if we’re 15,000 but in summer we’re 75,000,” Martha’s Vineyard Commission affordable housing and economic development planner Christine Flynn told the Gazette last year.

Ten Vineyard census employees will spend April updating address lists and performing a count of Island dwellings. Using this information, surveys will be sent out to be completed on April 1, 2010.

Mark Forrest, chief of staff for congressman William D. Delahunt, said yesterday that the seasonal population shift is at the root of a never-ending funding battle.

“We have a tax burden for the infrastructure which falls disproportionately on a smaller, less affluent year-round population. We have the burden of supporting a large, fluctuating population,” he said, “and we’re constantly fighting the perception that the Cape and Islands is the land of the rich.”

Mr. Forrest predicts the predicament will be reflected in the apportioning of the recent federal stimulus package.

“I think we’re geared up for getting more than we’ll end up getting,” he said. “We often feel unfairly singled out to get hit at the schools level and for clean water needs and roads and bridges. There’s a perception [among Cape and Islanders] that we’re not getting our fair share, and that’s a perception [the congressman] shares.”

There is $250 million in federal stimulus money marked for census outreach, to help make more accurate counts of displaced residents and illegal immigrants. Mr. Forrest said it was unlikely that any of this funding will be directed at the Vineyard.

“If officials [on the Island] are willing to make a case that there needs to be more outreach for the Island census, we’re willing to sit down with them,” he said.

Economist John Ryan dealt with the difficulties of quantifying a Vineyard population while compiling an economic study of the Island for the Martha’s Vineyard Commission last year.

“The census count is not going to be an accurate figure for the Vineyard,” he said. “It plays to the disfavour of the Vineyard being in April, it’s never going to be satisfactory. Places with a transient population have to accept to some degree that they can’t get an accurate picture,” said Mr. Ryan. “Month to month it varies so much more than a suburban area in Boston.”

Though the census bureau stresses that individual information collected remains private, the perception remains that answering questions about, housing status, age and race, may expose those with illegal status.

“It raises issues of fear,” he said, adding that even flat Islandwide numbers on race can be perceived as potentially threatening information.

“[The census bureau] has to be conscious of the reality that they’re dealing with uncertainty and vulnerability,” he said.

Michael Tholl, early local census office manager for Southern Massachusetts, made the 10 Vineyard hires, based on tests conducted earlier in the year at the Katharine Cornell Theatre.

“We want to be extremely accurate because if questionnaires are not returned we have to send out a crew for a physical one-on-one interview,” he said. “There’s a strict set of guidelines. Every one is counted and only once.

“The objective is to count everybody so the Vineyard gets its share of the $300 billion,” Mr. Tholl said.

They will work between 20 and 40 hours a week from the first week in April until June and may be re-hired next year to help perform the census.

Mr. Ryan said getting as good a picture of the population as possible is extremely valuable, the unknowables notwithstanding.

“There’s no excuse to not try to get as accurate a picture as possible of the people who live here. For example to gauge the Brazilian population,” he said, “the size of the group, their intentions, how long they’re going to stay. It’s very important from an economic point of view.”