The D.C. Board of Elections and Ethics yesterday refused to place an educational tax credit initiative on the November ballot, saying that more than 82 percent of the signatures of registered voters calling for the referendum were collected illegally.

The elections board rejected 22,624 of the 27,000 signatures collected, leaving the measure far short of the 14,000 signatures needed for a spot on the ballot. Elections Board Chairman Albert J. Beveridge accused the initiative's backers of "a manipulation of the petition process" by paying seven out-of-towners to move to Washington, register as D.C. voters without any intent to live here and then circulate the signature petitions.

Some of those seven persons, who collected the 22,624 signatures that were invalidated, may have since left the city, according to testimony before the board. Under D.C. Law, only registered voters who intend to live here can collect petition signatures, and only city residents can be D.C. registered voters.

The initiative proposal would have allowed each D.C. income tax payer to claim up to $1,200 credit for each child they helped support in either public or private schools. Expenses for books, transportation, tuition and other costs could have been claimed.

The opponents of the tax credit initiative, including a coalition of city officials called Save Our City (SOC), had charged that the initiative was being pushed by the National Taxpayers Union and the Libertarian Party, who were using Washington as an experimental laboratory for a referendum that failed to make it onto the ballot in California. Those initiative opponents were obviously pleased with the ruling.

Council member Wilhelmina J. Rolark (D-Ward 8), chairwoman of the SOC legal committee which challenged the petition signatures, said that yesterday's ruling "should make people very careful about how they come into the District of Columbia and try to wreak havoc on the electoral process. We know how to protect ourselves." Two other opponents of the initiative, Mayor Marion Barry and City Council Chairman Arrington Dixon, also praised the ruling.

H. Richard Mayberry, the attorney for the initiative backers, said that the D.C Committee for Improved Education, the group promoting the referendum, would probably appeal the board's ruling to the D.C. Court of Appeals, which would now have jurisdiction over the matter.

In announcing the decision, Beveridge said that the "single important piece of evidence" that the board considered was a document, produced by the SOC challengers, that showed one petition circulator -- Elbert C. Blackwell III -- had signed a petition in North Carolina April 20 stating that he wanted to help start a Libertarian Party chapter in that state and that he intended to vote in the next North Carolina election.

However, just four days earlier, on April 16, Blackwell had registered to vote as a District of Columbia resident.

Blackwell, reached by telephone in Raleigh, N.C., said he registered as a D.C. voter and he "probably did" sign the North Carolina petition four days later. But he added that when he moved here in March, "I did intend to stay in D.C." to work for the National Taxpayers Union. He said he moved to Raleigh after the petition drive.

Beveridge said it was up to Mayberry and the petition backers to explain the inconsistency in Blackwell's two voting registrations, but the elections board chairman noted that during the hearings, Mayberry did not produce any of the seven signature collectors as witnesses and did not offer any explanations as to their current whereabouts.

Mayberry said that it would have been "very dangerous" to bring any of the petitioners forward as witnesses. He said that the U.S. Attorney's office here is weighing a possible criminal investigation into the matter and witnesses at an administrative hearing are not given the same legal protections as they are in normal court proceedings. Also, Mayberry said, "Some people are better witnesses than others. Some cannot stand the scrutiny."

But the opponents of the measure charged that the initiative would have badly drained the city government's treasury, costing the city at least $30 million a year.

The opponents, some of whom privately voiced fears that the measure might pass, attacked it on legal technicalities and filed five separate challenges in an effort to knock it off the ballot one way or another. The elections board denied four of those challenges for various reasons, but ruled in favor of the challengers on the fifth issue, the issue of the illegal petition circulators.