IF YOU ARE a registered voter in the Eighth Congressional District in Massachusetts, you could vote for a Kennedy in tomorrow's Democratic Congressional primary. Joseph P. Kennedy, who has help the office for six years, is being challenged by Charles C. Yancey, the Boston City Councillor.

But, Yancey would argue, name recognition is no good reason to cast your vote. And running against a Kennedy in this region, he would know. At the very start of the Eighth District's congressional campaign, Kennedy was, in Yancey's words, "anointed" by the local media, and Yancey hasn't got a word in edgewise since. Television and newspapers have not even bothered to cover debates between Yancey and the incumbent.

YET DESPITE Kennedy's unfair advantage, his six-year record in support of poor and working-class citizens is nearly unmatched in the House. He has displayed dogged support for bills which create social programs benefitting not only his constituents, but also the nation. Massachusetts cannot afford to lose a representative with as much clout and conscience as Kennedy.

His accomplishments read like a wish list for a liberal-minded city like Cambridge. Kennedy has made affordable housing one of his key priorities, and has passed legislation which appropriates $300 million to new housing programs--the largest new allocation in a decade. He has also kept developers from converting low-cost housing units into condominiums.

The Black Congressional Caucus gave Kennedy a 100 percent approval rating, endorsing every vote he made as a representative. Kennedy has also fought to force banks to disclose their loan approvals in their communities to prevent "redlining" practices which discriminate against minorities.

Yancey, who is Black, has a nine-year record as Boston City Councillor and has shown a similar drive for social reform and economic development. His efforts led to the reopening in 1984 of Boston fire and police stations closed by Proposition 2 1/2, and he wrote legislation which called for the city of Boston to divest from South Africa.

IN A NUMBER OF CASES, Kennedy has faltered, showing that his predilection for social programs has often led him to neglect the bigger picture of the economy. For instance, Kennedy voted in favor of the proposed balanced budget amendment this summer, joining the crowd which tried to free itself from the realities of fixing the economy by offering their constituents an empty answer to real economic fears. Yancey opposes the amendment. Still, as head of the Clinton-Gore Massachusetts campaign, Kennedy supports the candidates' mandate for deep economic change and investment in the infrastructure.

Also, Kennedy has supported the death penalty in Congress. We cannot agree with this position, and are disappointed that a man with such progressive views clings to this archaic policy. But like our endorsement of Bill Clinton, another politician in favor of the death penalty, we have weighed this position with Kennedy's other positions, and find him an asset to the state.

Clearly, Joe Kennedy has some problems. He isn't a mental giant (how many members of Congress are?)--his speech last year against the Gulf War drew criticism from the local media for its shallow understanding of the issues involved.

BUT IN A CHOICE between two candidates with similar views, Massachusetts needs someone who has proved that he can make these policies reality. Yancey, despite his efforts on the local level, has not effected change anywhere near the scope Kennedy has done.

But the media should have given Yancey more of a chance; their neglect of the candidate was wrong. That television and newspapers chose to "anoint" a man for his incumbency and family name is a danger to the democratic process. We hope that in the next campaigns, the media, ourselves included, will give people like Yancey a fair chance.

Despite his deficiencies and unfair advantage, Kennedy remains a leader in social change. And his work and experience in Congress outweigh the advances Yancey has made in Boston.

IN THIS YEAR of anti-incumbent fervor, Massachusetts must be careful not to lose one of its best legislators. With an extended stay in Washington, he could bring about even greater change for the nation with his idealism and effective, vocal leadership.