An exhaustive study of hiring policies for head and assistant coaching positions in the National Football League over the past 20 years clearly demonstrates a pattern of discrimination against blacks, the NFL Players Association charged yesterday.

Moreover, contended Edward R. Garvey, NFLPA executive director, at a press conference, "The Study shows that in recent years they're (the NFL) getting worse. Something has to be done."

Commissioned by the NFLPA, the year-long study was done by Jomills Braddock II, a sociologist with the Center for Social Organization of Schools at Johns Hopkins University in Baltimore. The study entailed examination of data and records of more than 5,000 NFL players between 1960 and 1979, and it was said by Garvey to have been the "most important study of hiring patterns in the NFL."

In the 20 years since 1960, the study showed, a total of 261 assistant coaches and 68 head coaches have been hired from the ranks of former NFL players. Although 26 percent of the NFL players during that period were black, there were no black head coaches hired and only 20 black assistant coaches. Currently, approximately 50 percent of the NFL players are black. c

Garvey said he will ask a blue ribbon panel to be convened by William Pollard, director of the AFL-CIO's department of civil rights, to study the matter with NFL officials.

NFL headquarters in New York said Commissioner Pete Rozelle was traveling and would not be available for comment. But Jack Donlan, executive director of the NFL Management Council, suggested release of the study could be related to a running dispute between Garvey an the corps of professional agents who negotiate contracts for individual players.

"You've got to question his timing," said Donlan. "Instead of trying to resolve the issue, he's making a speech about it."

In Washington, Edward Bennett Williams, president of the Redskins, said, "There is no discrimination in the Redskins organization." There are no blacks on the Redskin coaching staff, Williams said, but he noted the No. 2 man at Redskin Park, Bobby Mitchell, is black, as is Charley Taylor, the director of college scouting.

Said Braddock yesterday, "We found strong suggestions that race does matter in managerial recruitment in professional football. Race exerted a larger direct or independent effect than three other predictors -- educational attainment, central position assignment (the so-called leadership poistions of center, guard, linebacker and quarterback) and the player's professional accomplishments."

Excluding considerations of race but including the other factors, it would be reasonable to expect there to have been 92 black assistant coaches and 10 black head coaches in the NFL during the last two decades, Braddock said.