A University of Virginia demographics group recently released preliminary estimates of school-aged populations throughout the state.

The numbers determine the amount of the state sales and use tax given to each school division for next year’s budget.

For the first time, the state will use estimates from the University of Virginia’s Weldon Cooper Center for Public Service instead of numbers collected by the school divisions to determine each division’s slice of the pie for the 2012-2014 biennial budget.

The Cooper Center estimates Suffolk has 18,856 individuals ages 5 to 19. The new estimate equals about 100 more people than the number from a 2008 census of Suffolk Public Schools.

Cooper Center statistician Susan Clapp said these are preliminary estimates, and she hopes the final numbers will be ready for release by the end of October.

With the numbers released, Cooper Center researchers are now meeting with school divisions that believe the estimates are either too low or too high.

She said the researchers are open to hearing the divisions’ concerns and adjusting their numbers if they find evidence that warrants a change.

“We want to make sure our numbers are in line with what they know about their locality,” Clapp said.

Suffolk Public Schools has not contacted the center for a meeting, she said.

The General Assembly voted in 2010 to use the Cooper Center’s estimates instead of numbers derived from independent censuses conducted by each division every three years.

Clapp said the center evaluated the numbers from the 2008 censuses and found a lot of inaccuracies.

“There was so much variation on how it was done that we recommended the legislators switch to single methodology,” she said.

Clapp, who led the research effort, said about 2/3 of divisions in the state were under-counting their school-age populations, while many others were over-counting.

Cooper Center researchers want to get more precise population numbers in order to have the state funds more accurately distributed.

Clapp said these new estimates will result in some divisions getting more or less of the sales tax percentage, although she doesn’t know yet what divisions will be most impacted.

To reach the estimates, Cooper Center researchers used information from the 2010 U.S. Census to acquire the number of people ages 5 to 19 years old in each division.

However, the demographers were required to make adjustments in order to follow Code of Virginia rules for counting populations.

“The biggest impact (on the numbers) comes from college students,” Clapp said.

For example, if a student from Fairfax is attending Old Dominion University, the U.S. Census counts him as a resident of Norfolk, but the Code of Virginia still would count him as a resident of Fairfax.

Clapp said the demographers had to adjust their estimates to move about 3,500 college students from their school’s cities to their home cities.

The center also made similar adjustments for 500 to 600 school-aged individuals in the Department of Corrections and the Department of Juvenile Justice.

Population numbers for all school divisions are available at www.coopercenter.org/demographics.