The Maryland State Board of Education, seeking to quell a controversy over a high school writing test, voted unanimously yesterday to delay making the test a requirement for graduation.

The vote, taken at a board meeting in Rockville, moved back the graduation requirement from spring 1987 to spring 1988. It followed the recommendation of State Superintendent David W. Hornbeck, who announced last month that he supported a change in the timing of the writing test program after legislators threatened to pass a bill delaying the graduation requirement until 1989.

Under the board's procedures, the public now has 45 days to comment on the test, and the board will take a final vote on the measure at its August meeting.

The functional-writing test has been criticized by educators, students and parents, who point to the high percentage of students failing the exam. More than 25 percent of the 55,000 juniors statewide have failed the test.

James Coles, principal of Thomas S. Wootton High School in Rockville, where 34.5 percent of this year's juniors failed the test last spring, praised the board's vote.

"That's a positive step forward in terms of clearing up the cobwebs that are in the scoring and grading of those tests," he said. "Once they get those things straightened up we'll be able to deliver a better package to our students.

Functional writing is described by educators as organized, common sense writing needed to comunicate thoughts or ideas such as those found in business letters or letters to friends.

Twenty-two states give students writing assessment tests, but only Maryland, Nevada and New York have made the writing test a graduation requirement, according to a 1984 report by the Education Commission of the States, an educational clearinghouse.

Maryland's two-part essay test has been questioned because it discards the brevity standard held by educators nationally for 15 years in favor of more elaboration in writing style. The essays -- one narrative and one explanatory -- are graded for content, organization, audience, sentence formation and convention.

Critics also question the way in which out-of-state graders -- who average 60 to 70 seconds on each essay -- scored the test.

"They finally had to admit they weren't grading grammar or punctuation, they were grading content. It boiled down to grading kids' comments," said William Henry, spokesman for the Montgomery County schools.

Educational Testing Service of Princeton, N.J., which evaluated the test for the state this year, recommended:

*Establishment of a procedure that allows a student who fails the test to appeal the grade.

*Automatic review for all students who fail the test by half a point.

*Formation of a committee of Maryland teachers to work with the staff of the State Department of Education in approving the test questions, defining functional writing, reviewing the scoring guide and participating in the scoring sessions.