Donald Trump fields questions at The Family Leadership Summit at Stephens Auditorium on July 18, 2015 in Ames, Iowa. Scott Olson/Getty Images

A new poll by ABC and the Washington Post puts Donald Trump at the top of the GOP's 2016 field, but anyone wondering if his criticism of Arizona Sen. John McCain has damaged his candidacy will have to keep waiting.

Conducted from Thursday to Sunday, the poll can't accurately gauge if Trump's Saturday remarks -- calling McCain "not a war hero" -- have lessened Republican voters' enthusiasm for him.

McCain, a Navy pilot, was held as a prisoner for more than five years during the Vietnam war. Veterans and politicians from both parties lambasted Trump for his comments, but he declined to apologize.

"What happened is, later on, the Republican candidates -- some of whom are registering 1 percent and zero -- and they’re very upset that I’m leading the polls by actually a nice margin," Trump told ABC's This Week. "They’re extremely upset."

The poll had Trump on top at 24 percent, with Wisconsin Gov. Scott Walker in second with 13 percent support of those polled. A Monmouth University poll of Iowans was also conducted from Thursday to Sunday and released on Monday. It showed that Scott Walker continues to maintain a lead at 22 percent in the Iowa Republican caucus, with Trump following at 13 percent.

"Rankings in a single-choice poll can be swayed by a tiny shift in public opinion," The New Republic reported. "Conventional polls, by themselves, do not predict whether Trump will survive -- like [Mitt] Romney did -- or fizzle out after a few months."

Polls can take days or even weeks to reflect the impact that news events have on public opinion. And with the election still 16 months away, the polls may reflect name-recognition more than favorability -- an advantage for a candidate whose last name is blazoned on skyscrapers.