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President Obama and Mitt Romney are running essentially even not only in vote preferences but also in voter contact, a critical element of a race so close the campaigns' ground games could well make the difference.

As their field teams go into overdrive, some underlying shifts toward Romney paused in the latest ABC News-Washington Post poll. Still, the race itself is essentially unchanged: 49-48 percent among likely voters, compared with 50-47 percent Thursday.

See PDF with full results and charts here.

After advances earlier this week, there's no further gain for Romney on key economic measures in today's poll, produced for ABC by Langer Research Associates. And strong enthusiasm among his supporters, which rose sharply after the first debate, has been essentially stable since - neither losing nor gaining more ground, and even with Obama, but not ahead.

Those results make the campaigns' get-out-the-vote efforts potentially pivotal. While 22 percent of likely voters personally have been contacted by Obama's campaign, as many, 23 percent, have been contacted by Romney's side. That's tightened from a 5-point Obama advantage in contacts in mid-October; Obama similarly had a 7-point advantage over John McCain in contacts at about this point in 2008.

More important, Romney has caught up in the efficiency of his outreach as well. Among likely voters who've been contacted by his campaign, 63 percent, indeed, are Romney supporters. That's on pace with Obama, who has had 65 percent efficiency in his campaign contacts. It's a measure on which Obama led Romney by 17 percentage points two weeks ago, and was ahead of McCain by 22 points at this time in 2008. Efficiency matters because contacts are meant to encourage turnout; the campaigns want to reach, and encourage, their supporters.

Romney also has sharpened his turnout efforts in the 10 states now designated by the ABC News Political Unit as battlegrounds (see the end of this report for the list). There, 40 percent of likely voters have been contacted by the Obama campaign, 39 percent by Romney's. Efficiency is numerically better for Obama, but within the margin of error for this subset of the population.

Obama led Romney by 13 points in contact in these states two weeks ago; again, Romney has caught up - not ahead, but even.

VOTING - Voter contacts matter all the more given the increasing prevalence of early and absentee voting. Just 61 percent of likely voters in this survey say they plan to vote on Election Day; the rest either plan to vote early or, in the case of 8 percent, already have done so.

And there's a difference in these groups: Among people who say they plan to vote early (or have done so), Obama leads in vote preferences by 55-42 percent. Among those who plan to hold off until Election Day itself, those numbers reverse - a 10-point Romney advantage, 54-44 percent.

TRACKING TRENDS - The ABC-Post tracking poll, based on a four-day rolling average of results, showed improving trends for Romney through Wednesday night; as reported Thursday, these took him to his first clear lead over Obama in trust to handle the economy, and his first virtual dead heat in who better understands Americans' economic problems.

Those now have stabilized. Romney, for instance, went from an insignificant plus-2 points in trust to handle the economy in four nights of interviews completed Sunday to plus-9 points in those completed Wednesday; it's plus-7 now. On empathy, Romney went from minus-9 points in mid-October to minus-7 Sunday and minus-2 Wednesday; in the latest interviews it's steady at minus-2, with no further advance. Both are key measures to watch in an election framed by the longest, deepest economic downturn since the Great Depression.

GROUPS - Those shifts in sentiment, as reported previously, occurred chiefly among white men, especially those who lack a college degree. Romney is at another new high in the latest poll among white men, with 66 percent support, lifting him to 60 percent among whites overall, tying his best of the contest. Whites account for 75 percent of all likely voters.

Political independents have shifted as well, to a campaign record 58-38 percent, Romney-Obama. As with the other results, that reflects a move toward Romney among lower-income white independents and among independent men. Additionally, more conservative independents say they'll vote, and prefer Romney.

One apparent impetus, as noted Thursday, is that independents are disproportionately likely to say their opinions of Romney improved as a result of his performance in the debates.

Leading among independents doesn't tip the race to Romney because Democrats slightly outnumber Republicans, by 4 points among likely voters, and Obama wins nearly all Democrats (as does Romney with Republicans). Democrats outnumbered Republicans by 7 points in the 2008 exit poll.

Obama's at a new high among blacks in this poll, with an almost unanimous 97 percent support, lifting him to 82 percent among nonwhites overall, also his best to date. And a wide gender gap continues - Romney plus-18 points among men, Obama plus-13 among women. The result among women is typical; it's Romney's lead among white men that's making the race so close. They constitute 37 percent of likely voters. The question is whether that's enough to keep Romney's post-debate momentum moving.

METHODOLOGY - This ABC News-Washington Post poll was conducted by telephone Oct. 22-25, 2012, among a random national sample of 1,382 likely voters, including landline and cellphone-only respondents. Results have a margin of sampling error of 3 points, including design effect. The survey was produced for ABC News by Langer Research Associates of New York, N.Y., with sampling, data collection and tabulation by Abt-SRBI of New York, N.Y.

Partisan divisions in this survey, Democrats-Republicans-independents, are 34-30-32 percent among likely voters. Partisan divisions in the 2008 exit poll were 39-32-29 percent. "Battleground states" as designated by the ABC News Political Unit are Colorado, Florida, Iowa, Nevada, New Hampshire, North Carolina, Ohio, Pennsylvania, Virginia and Wisconsin.