A new think-tank study released on the eve of the 2010 Census has some eye-opening news about the decennial count's import for Floridians: In a national ranking, the amount of Census-based aid flowing to the state and the three-county South Florida region puts both in the bottom five.

The spread between the federal aid flowing to Florida and the top-ranked states based on Census population figures is significant, according to a Brookings Institution report released Tuesday.

Among the top states, Vermont and New York receive $2,873 and $2,301 per resident, respectively. Florida, by contrast, gets $901 per resident, better only than Nevada, Virginia and Colorado. The national average is $1,469 per person.

Broward and Miami-Dade counties each ranked well in the bottom half of the nation's 200 biggest counties.

The Brookings Institution report is the first comprehensive examination of the more-than $400 billion worth of federal aid to programs that use Census population figures as a basis for distribution.

The study doesn't get into the reasons for the disparities. Its author says the principal cause may be Florida's relatively stingy Medicaid program, which limits the federal dollars flowing into the state. Medicaid spending accounts for nearly 60 percent of the money distributed to states based on Census data.

But what the study does confirm, said author Andrew Reamer, is what Census boosters have argued for years: That ensuring as accurate a count as possible can increase the flow of federal money to states and localities from some 215 government programs, including healthcare for the poor, highways and transportation and schools.

And that is especially significant this year, he said, when the Obama administration's economic stimulus program will pump even more into states and communities based on Census results, boosting the total to be distributed to well over $500 billion.

``States that are less aggressive are going to lose out,'' said Reamer, a fellow at Brookings's Metropolitan Policy Program. ``The allocation among states for many programs is based on population counts, or parts of the population like the number of kids in poverty. It's a zero-sum game, so it's in every state's interest to raise its population numbers.''

Why Florida fares relatively poorly cannot be explained from his study, Reamer said.

But the state's income eligibility level for Medicaid, the healthcare program for the poor, is high compared to most states', he noted. That means many poor people who could qualify for coverage -- and draw additional federal reimbursement to Florida -- do not.

Another factor: States and the federal government share Medicaid expenses, with the level of federal reimbursement set according to poverty levels. Because Florida's percentage of poor is close to the national average, federal reimbursement rates are relatively low.

Because of how the formula works, however, boosting the state population count would increase the percentage of the population in poverty, Reamer said. Florida would collect $792 for each resident added to its Census count in 2010 from Medicaid alone, Reamer said.

``I do get the sense that Medicaid explains a lot,'' Reamer said. ``Florida, when it comes to covering working parents, is very conservative. The state is not spending a lot of money on Medicaid or children's health insurance relative to other states, but the other result is that it's not getting as much from the federal government.''

Since Florida is also competing with other states for limited funds for highways and transportation, schools and housing grants, ensuring as full a count as possible would likely boost its chances of getting its fair share of aid, Reamer said.

Another possible factor in the disparities in aid distribution might be a significant undercount of the state's minority and immigrant populations, particularly in South Florida. Demographers say past head counts have missed significant numbers of African-American, Hispanic and immigrant residents of the state, who tend to be poorer and could help the state and localities qualify for additional federal aid.

The report's release was timed to coincide with the start of the decennial head count. Census forms will begin hitting mailboxes on Monday.

Although the Census Bureau has estimated the amount of federal aid that hinges on Census 2010 figures at more than $400 billion annually, no one had looked at how aid has been distributed, Reamer said. The money includes Medicaid -- which accounts for $260 billion, or 58 percent of the total -- as well as $37 billion for highway construction, $23 billion for education and Head Start, and $15 billion in housing vouchers, among other programs.

What Reamer found was confirmation of the Census Bureau's estimate and wide variation in aid received by state, county and region.

The vast bulk of the money, more than 80 percent, goes to states, which then distribute a portion to local governments. Counties and municipalities can also receive some aid directly.