State Sen. Jamie Raskin, along with fellow Democratic candidates seeking to represent Maryland’s 8th District in Congress, speaks during a forum on Oct. 1. (Evelyn Hockstein/for The Washington Post)

Maryland state Sen. Jamie Raskin released a poll Monday that shows him with a nine-point lead over his principal opponent, Kathleen Matthews, in the Democratic primary race to represent the state’s 8th Congressional District.

The survey of 500 likely Democratic primary voters, conducted by GBA Strategies on behalf of the Raskin campaign, found 30 percent supporting Raskin (D-Montgomery) and 21 percent backing Matthews, the former news anchor and Marriott executive. Twenty-eight percent remain undecided.

The poll showed only one other candidate, Del. Ana Sol-Gutierrez, in double digits, with 11 percent support. Del. Kumar Barve (5 percent), David Anderson (3 percent), Will Jawando (2 percent) and Joel Rubin (less than 1 percent) lagged far behind.

While the methodology of the poll appears sound, in general, polls commissioned by a specific political candidate tend to favor that candidate.

Raskin enjoys the highest favorability ratings, according to the poll, 5-to-1 compared to 2-to-1 for Matthews. Raskin also had a significant advantage among voters who say they are familiar with both him and Matthews.

While many voters remember Matthews favorably from her long career at WJLA (Channel 7), only 48 percent of those likely voters support her candidacy, according to the poll. Raskin is supported by 74 percent of those who view him favorably.

The survey said Raskin’s grass-roots support is strong outside of his state senatorial district, where he leads Matthews by 43 points. He has a 30-point margin over Matthews in the district where she lives, and a 21-point advantage over Sol-Gutierrez on her home turf.

Matthews campaign manager Ethan Susseles declined to discuss his candidate’s polling data. He said the Raskin survey confirms that the primary is a two-person race.

“This poll shows that a majority of Democratic voters are looking for a fresh approach and Kathleen has a track record of getting things done, putting women and families first, and the international experience we need in these challenging times,” Susseles said in a statement.

The primary will be held April 26.

GBA Strategies reached likely Democratic primary voters on landlines and cellphones between Oct. 28 and Nov. 1 The firm said the sample was drawn from a voter file based on previous Democratic primary vote history. The poll has a margin of error of plus or minus 4.4 percentage points.

(Updated at 11:20 a.m. with comment from Matthews campaign.)