A federal appeals court has ruled in favor of a historically black college in Tennessee that is fighting a faculty-unionization effort.

But the opinion, issued earlier this week, does not kill the union drive at LeMoyne-Owen College. A three-judge panel of the U.S. Court of Appeal for the District of Columbia Circuit found that the National Labor Relations Board had failed to adequately explain why it was ruling against the precedents cited by the college. The court sent the case back for further review by the board.

In 2002, the Faculty Organization of LeMoyne-Owen College petitioned the labor board to be recognized as a union. The college, citing the precedent set by the U.S. Supreme Court in a 1980 case involving Yeshiva University, argued that the professors had managerial roles and should not be allowed to unionize.

A regional director of the labor board ruled in favor of the faculty, but the college appealed to the full board, in Washington. The full board declined to review the ruling, finding that the college had raised "no substantial issues." But the college refused to bargain with the union and took the case to court.

Since the Yeshiva decision, the labor board has confronted numerous union drives at private colleges. It has ruled that professors at some institutions could form unions, while finding that professors at others held enough managerial roles to make them exempt from federal labor law.

For instance, in a 1990 case involving Lewis & Clark College, the board found that professors at the Oregon institution were managers in part because of the faculty committees that helped set academic policy. But in a 1997 case involving the University of Great Falls, the board ruled that professors on the Montana campus could unionize, noting that a dean had refused to let them use the textbooks they wanted.

In its unanimous ruling this week, the three-member appeals panel said that in the LeMoyne-Owen case, the labor board's regional director had reached his decision without mentioning any of the cases the college had cited. The labor board must explain how its ruling comports with contrary rulings in cases like the one at Lewis & Clark, Judge John G. Roberts wrote for the panel.

"The NLRB may have an adequate explanation for the result it reached in this case," he wrote. "We cannot, however, assume that such an explanation exists until we see it."

The college will continue to argue that the professors have managerial status. James G. Wingate, the college's president, said that professors are an important part of LeMoyne-Owen and that the administration would continue to work with the faculty.

Cheryl Golden, president of the faculty union and a professor of psychology, said the faculty members remain determined to unionize. "This decision does not reverse our thinking by any means," she said. Ms. Golden emphasized that the appeals court did not actually rule against the faculty union, but instead found the labor board's legal reasoning inadequate.

"If there was not a case for unionization for the faculty," she said, "the court of appeals would have clearly stated that."