After spending millions of dollars and untold energy to register voters this year, Republicans and Democrats are running neck and neck in registration drives in five battleground states, while Democrats have made notable gains in two others, a survey of recent figures suggests.

Neither party has gained a significant registration advantage in such hard-fought states as Florida, Colorado, Nevada, New Hampshire or New Mexico, a Washington Post study shows.

The strongest gains for one party belong to Democrats in Pennsylvania and Iowa.

Still, advocates and analysts said the unprecedented efforts by political campaigns and independent groups leave them better placed and better funded than ever to get new voters to the polls in what is expected to be a very close presidential election.

“It’s a sign that these organizations are warming up for the main event, which is turnout,” said Donald P. Green, a political science professor at Yale. “In this race, which is so close, if a campaign registers a person and knows where to find that person, they will do whatever they can to get them to vote.”

A review of the most recent registration figures shows:

• In Iowa, Democrats have registered four voters for every new Republican voter since 2000. Since this year’s caucuses, Democrats have outregistered Republicans by 9 to 1, closing the GOP lead in registration statewide to about 8,000.
• In New Mexico and Colorado, Republicans have outregistered Democrats by about 1 percentage point each.
• In Florida, Republicans have registered slightly more voters than Democrats have. Rolls have grown by more than 1 million since the 2000 election in the state that President Bush won by 537 votes. But nearly half of the new registrations have come from less predictable independents and small-party loyalists.
• In Nevada, there is a 1 percent increase in the other direction, with Democrats overtaking Republicans for the statewide registration lead.
• In New Hampshire, Democrats made up some ground, but they continue to lag behind Republicans in statewide registration by 40,000 voters.

Appraising the registration drives is a dicey business, cautions Curtis Gans, director of the Committee for the Study of the American Electorate.

Gans, noting that “registration doesn’t necessarily speak to turnout,” said voter rolls grew nationally in 1996 and 1998, largely because of motor voter laws, but turnout was down in both years. In 2000 and 2002, by contrast, registration was down but turnout was up.

“My instinct is we’ll have higher turnout this year because of interest in the election,” Gans said, “but it won’t necessarily be connected to registration.”