MORE THAN A YEAR out from the 2020 US Senate primary, Massachusetts Democratic voters strongly favor Congressman Joe Kennedy over Sen. Ed Markey, according to an online poll conducted last weekend.

When respondents were pressed to make a choice, Kennedy garnered 42 percent support compared to Markey’s 25 percent. Businessman Steve Pemberton earned 7 percent and attorney Shannon Liss-Riordan got 5 percent. Without leaners, Kennedy’s 17-point lead is slightly diminished, as 31 percent of respondents said they would back Kennedy compared to 19 percent supporting Markey.

The survey obtained by CommonWealth was conducted by Change Research, a San Francisco area firm that has worked on behalf of Democratic candidates and causes as well as the NAACP and the AFL-CIO, according to its website. The poll was commissioned by Education Reform Now Advocacy, which tacked the horse race and other political questions onto a bigger poll gauging voters’ temperature about education policy issues.

Unlike a traditional telephone poll, Change Research conducted its research online, and weighted its results based on demographics as well as the 2016 vote.

The margin of error for the Democratic primary was 3.5 percentage points, and the margin for general election questions was 3.1 percentage points, according to the pollster. Change Research is led by Mike Greenfield, who was the first data scientist at PayPal and LinkedIn, and the firm advertises affordable and accurate digital polling.

Run from August 23-25, the poll of 1,008 registered Massachusetts voters captured their feelings about the burgeoning US Senate race about a week after news broke that Kennedy might challenge Markey in the primary, but just before Kennedy publicly confirmed those news stories with a Facebook post on Monday. A total of 808 respondents weighed in on the Democratic primary.

Coverage of the potential Kennedy-Markey showdown has included whispers about internal polls that supposedly showed Kennedy with an advantage, but no public polls have yet provided firm data on the contest, which is more than a year out.

It was the exercise of a poll itself – presumably an internal one – disclosed by respondents that launched the initial parade of speculation that Kennedy was seriously considering taking on Markey. The 38-year-old scion of the Bay State’s most storied political family of the past century says he has new ideas, and he could make a case for generational change to voters if he goes forward with a campaign against the 73-year-old senator, who was closing in on his third full term in the US House when Kennedy was born.

Markey, who has secured the endorsement of Sen. Elizabeth Warren and 116 Democratic state lawmakers in Massachusetts, has aligned himself with the most animating causes of the political left, signing on as Senate sponsor of the Green New Deal and backing Medicare for All legislation.

Meanwhile, Republican Gov. Charlie Baker would merit a lot of poll respondents’ support if he chose to run for Senate, the poll found.

Baker would just squeak out a victory if the respondents to the poll were to decide a contest between Baker and the incumbent senator. When leaners were pressed to choose a candidate, Baker topped Markey 45-44 in the poll. Kennedy, meanwhile, would beat Baker 49-41, according to the poll, which found Baker would trounce Liss-Riordan 54-35 and Pemberton 56-31.

The results of last weekend’s poll are similar to other public surveys that have gauged Markey’s popularity with Massachusetts Democrats. A poll last September by Suffolk University/Boston Globe put Markey at 24 percent support against Congressman Seth Moulton at 18 percent in a hypothetical matchup for Senate. Last November, a YouGov poll for UMass Amherst found that in a hypothetical matchup with Attorney General Maura Healey, Markey received 26 percent support to Healey’s 27 percent.