Supporters of a D.C. educational tax credit initiative, who gathered about 27,000 signatures in a petition drive, have asked the D.C. Court of Appeals to reverse an Elections Board order throwing their referendum question off the November ballot.

The Elections Board ruled on Monday that 82 percent of the signatures could't be counted because they were gathered by seven out-of-town residents who were not properly registered voters, as required by D.C. law.

But sponsors of the tax credit plan, the D.C. Committee for Improved Education, argued that the board's action stripped petition-signers of their constitutional rights. They told the Appeals Court it also violated the Election Board's rule that "the failure of the circulator of a . . . petition to be a registered qualified [voter] will not invalidate" an otherwise qualified signature.

In a statement, Bill Keyes, chairman of the tax credit group, an offshoot of the National Taxpayers Union, denounced the three-member Elections Board as "political appointees . . . [who] have participated in the deliberate and orchestrated attempt by city government officials . . . to keep the people from voting for tax cridits."

After a random check of the signatures submitted, the elections board announced that an estimated 19,141 were valid, far more than the required 14,442. But it said that since so many were gathered improperly, the initiative still couldn't get on the ballot. The boardf also asked the U.S. attorney to investigate whether criminal charges should be brought against the out-of-town signature collectors.

The proposed referendum would allow taxpayers to deduct up to $1,200 per pupil from their D.C. income taxes for expenses at either private or public schools.