The presidential race has become a lot less clear over the last few weeks.  Back in mid-August, Hillary Clinton held a large lead over Donald J. Trump.  Since then, her lead has slipped — but how far isn’t so obvious. The various forecasting models and polling averages have split about as much as they have all year.  In mid-August, Mrs. Clinton led by around eight percentage points in national polling. Since then, there hasn’t been much evidence to confirm that large margin.  Yes, there have been a few polls showing her leading by a big amount. Monmouth, Quinnipiac and USA Today/Suffolk polls all showed her up by at least seven points nationwide.  But note that over the last two weeks there really hasn’t been any indication that Mrs. Clinton was up by, say, double digits. If she were still up by eight points, we would expect at least some data showing her posting huge margins.  In contrast, plenty of recent polls show a much tighter race. Many are less reputable, including online and automated polls of dubious methodological quality or with limited or no track records.  But there have been higher-quality polls with a smaller lead for Mrs. Clinton, and even the CNN/ORC poll this week that showed her down by two points among likely voters. A few weeks ago, there weren’t many polls of any kind showing her in that weak a position.  Gallup’s daily tracking poll — another live-interview measure — also showed Mrs. Clinton’s favorability ratings slipping over the second half of August, which has tended to track with changes in her overall standing in national polls.  The battleground state polling — even the high-quality polls — also shows a tighter race. Recent Marquette, Monmouth and Suffolk polls in Wisconsin and Michigan showed Mrs. Clinton with a modest lead, not the double-digit edge she had a month ago.  All considered, the balance of evidence plainly indicates that Mrs. Clinton has lost ground since mid-August. Whether she’s up by two or five points is another question. But it’s definitely not seven or eight anymore.  Exactly where you peg her lead — two points or six points or somewhere else — is a lot hazier than usual.  The differences are reflected in the big splits between the various polling averages and models, like at The Huffington Post or FiveThirtyEight.  Part of the issue is that there haven’t been many high-quality polls recently, and most (though not all) of the highest-quality surveys have shown Mrs. Clinton with a comfortable lead, as FiveThirtyEight’s Harry Enten pointed out last week.  On the other hand, the online and automated polls have shown a much more significant tightening of the race. The always noisy Reuters poll has shown a big decline in Mrs. Clinton’s support, and many of its new state polls have shown the same thing. So has Morning Consult, a new online pollster. A wave of polls from Emerson College, which does not contact cellphones, showed Mrs. Clinton with only a nominal edge in the battleground states. The Los Angeles Times/U.S.C. panel, which differs in a number of respects from other surveys, gives Mr. Trump a lead. Whether a polling average or model includes all of this data or some of it, or has the means to correct for including polls that systematically favor one candidate or another, might be a bigger issue now than it was a month ago.  Another issue is that the high-quality polls have given readers the opportunity to choose their own adventure, depending on what type of question they look at.  A recent Fox poll, for instance, showed Mrs. Clinton ahead by just two points. But it showed her ahead by six points in the one-on-one matchup, without Jill Stein or Gary Johnson listed as candidates.  The CNN/ORC poll showed Mrs. Clinton trailing among likely voters but ahead among registered voters.  These big gaps between registered and likely voters, and the four-way and two-way ballots, haven’t been the norm so far this year.  There’s no “right” answer about which is more reliable. I happen to prefer to look at samples of registered voters — a larger sample, and I can mentally apply a slight and consistent likely-voter penalty to the Democrats — but I know that generally the likely-voter numbers are more accurate. I’m agnostic about whether the four-way or two-way polls are better in this particular election, since Mr. Johnson and Ms. Stein blur the line between candidates who deserve inclusion and those who do not.  Most of the forecasting models and polling averages use the four-way race and likely-voter polls. Right now, those may offer a particularly pessimistic picture for Mrs. Clinton.  Late August is not a great time of year for polling, and Labor Day weekend is probably the worst of all. The news can slow down in August, and so can public interest in the race. People go on vacation. News media organizations that spent tens of thousands of dollars polling around the period of the conventions take some time off and wait to re-enter the fray in September.  Over the next few weeks, a lot of these questions are going to sort themselves out. There will be a new wave of high-quality polls. Many will add likely-voter screens for the first time. And not only will we have more new polls, but we’ll also be even closer to the election — and entering a period when the polls tend to be quite predictive of the eventual outcome.
She’s no longer leading by seven or eight points, but we’ll get a clearer picture soon of where she stands as high-quality polls roll in.