A new Wall Street Journal/NBC News poll finds Hillary Clinton expanding her lead over Donald Trump to 11 percentage points among likely voters, up from a 6-point advantage in September.

Below are some of the other major findings of the poll:

—While Mrs. Clinton is widely considered to have the superior voter-outreach and get-out-the-vote programs, the poll found that roughly the same share of voters had been contacted by either campaign. Some 31% said they had been contacted by the Trump campaign by phone, email and other means, while 32% said the Clinton campaign had contacted them.

—Mr. Trump has frequently questioned the accuracy of polls showing him behind. Some supporters say polls understate his strength, arguing that some people who plan to vote for Mr. Trump are reluctant to disclose their preference to pollsters or others.

The poll found that 13% of those surveyed said they knew people who supported the Republican nominee but were hesitant to say so, because they worried what others might think.