Give the three candidates in Prince William County's Woodbridge District this much credit: They've confounded the "experts" -- that circle of government officials, party leaders and reporters who in consultation with one other arrive at the "conventional wisdom" of how so-and-so is going to do in a coming election.

The Woodbridge supervisor race is considered so close that even Prince William's most cocksure prognosticators are not guessing which contender -- Democrat Hilda Barg, Republican Ella Shannon or independent Edward Rodriguez -- will win on Nov. 3.

The three candidates to succeed Republican Supervisor Donald E. Kidwell, who is retiring after two four-year terms, all bring certain strengths, but so far none has shown the political muscle needed to carry off a solid victory next month, according to observers in both parties.

As in several other races this year for the seven-member board, the debate in Woodbridge has seen clashes on the most effective and responsible tactics to manage Prince William's soaring growth.

The district, located in the far southeastern corner of the county, just across the Occoquan River from Fairfax County, became suburban in the 1950s and 1960s, the first part of Prince William to do so.

Many of the young, blue-collar families who moved to the area then have stayed. The district is among Prince William's most conservative, and aging issues have become increasingly important.

In recent years, new growth has brought in younger residents, many of whom live in town houses and travel to jobs in Fairfax, Crystal City or the District.

Although most of the Woodbridge District is developed, there are some unbuilt tracts, many of which won their zoning status years ago. At that time, local governments in Virginia did not have the power they now do to extract "proffers" -- concessions such as road construction, school sites or parks -- from developers in exchange for zoning approval.

Shannon, Kidwell's appointee to the Prince William Planning Commission, said her experience on that body has given her the know-how to grapple with this issue of "stale zoning."

By working shrewdly with developers, she said, the county's leverage can be increased and the impact of residential development can be softened. She said she supports Prince William's recent efforts to buttress its tax base by luring commercial and industrial development.

Shannon, a 51-year-old Pennsylvania native who moved to the area in the 1950s when she and her husband were employed by the Army, said she became involved in politics through school and civic affairs, which she said had given her an appreciation of citizen concerns.

Shannon, a real estate agent, scoffed at criticisms from Barg that her job compromises her objectivity on development issues. "Nothing could be further from the truth," Shannon said.

Of the three Woodbridge contenders, Barg has advocated the most drastic measures to control growth. She has said the board should reject all development that would have an adverse impact on Prince William's services and quality of life. Opponents have said that approach is irresponsible and could not be defended in court.

A centerpiece of Barg's campaign is elimination of the county's personal property tax, levied on boats, cars and other vehicles. Barg has said the lost revenue could be recouped by raising the sales tax.

Barg, 54, is from the Potomac River community of Cherry Hill, and stresses that she is a Prince William native. A former businesswoman, she said she could devote herself to serving on the board.

Independents rarely win in Northern Virginia elections, with the exception of those who are federal employes barred by law from partisan activity but who nonetheless have the support of Democratic or Republican activists. Rodriguez, 38, a Vietnam veteran and the president of the Newport subdivision homeowners association, is given a far better chance than most, political observers say.

Rodriguez, who works out of his home for an Annapolis electronics firm and who was once active in local Democratic politics, said he decided to seek office after noting what he describes as the poor quality of the other candidates. He said his election would present an alternative to the "in-house fighting" that sometimes engulfs the supervisors, particularly in electing a chairman each year.

Rodriguez, a member of the Prince William Chamber of Commerce, has stressed what he describes as his ability to balance the county's need to expand the business sector while bringing residential growth, especially in areas with "stale zoning," under tighter rein.

"We've got to produce incentives for employment here in Prince William," he said.