When James (Doc) Williams took over as principal of Cardozo High School three years ago, it had a high absenteeism rate, low test scores and a reputation as one of the worst of the District's 14 high schools.

Williams was undaunted. "We don't have any bad students here. We have students that have bad habits," he said then. "They are just waiting for a leader to come along and say we're going to deliver you a good school."

Yesterday, Williams' promise bore fruit.

Standardized test results released yesterday showed Cardozo students making what D.C. School Superintendent Floretta D. McKenzie called one of the most dramatic single-year improvements in test scores in the nine years since city schools started administering the Comprehensive Tests of Basic Skills. See story on Page A8

The test scores of this year's Cardozo 11th graders still remain below grade level. But in some subjects, test scores were raised as much as two grade levels. Eleventh graders last year scored at the eighth-grade level in reading and mathematics. This year, 11th graders scored above the ninth-grade level in reading and at the 10th-grade level in mathematics.

Last year, Cardozo's overall test scores were the lowest of the city high schools. This year, the school, at 13th and Clifton streets NW, ranks eighth out of the 14 high schools.

Cardozo's progress, which Williams credits to a comprehensive plan of preaching, teaching and tutoring, is of particular interest to school officials concerned about poor test scores of some students at other senior high schools. Test scores released yesterday by D.C. school officials showed that elementary and junior high school students improved or held their scores steady but that 11th graders continued to score well below the national average and were below grade level in every area tested.

McKenzie, announcing the test scores at a morning news conference, said that secondary school improvement would be a priority in the coming year. And, she said, Cardozo's programs and Williams' leadership will be studied and could serve as the focus of a program for city high schools.

Cardozo's principal, a 17-year veteran of the school system, credits the school's success mostly to a return to the basics.

Williams, 42, who stands 6 feet 3 inches and looks as though he can hold his own with any professional football team, said he had a simple and direct message when he took over in 1983. "I told them that this school needs to be cleaned up and I'm the man to do it."

Cardozo, which sits atop a hill in the heart of a drug-infested neighborhood where 40 percent of the residents are high school dropouts and the unemployment rate is the city's highest, has been best known in recent years for its marching band, which performed at the Tournament of Roses Parade in Pasadena in 1981. Everything else about the school was a "joke," said School Board member Wanda Washburn of Ward 3.

But she is quick to point out that "no one laughs at Cardozo anymore."

Williams said he immediately put into place a comprehensive plan that included constant "preaching" to students about improving their attitude toward life, an intensive effort to curtail absenteeism, daily test-preparation courses for all students and tutoring for those who tested in the lowest percentiles.

Williams said he wanted to teach his students the worth of hard work and self-respect. A poor education, students were told, would lead to a life of crime and poverty, while a good one "opens the doors of opportunity."

Williams' lectures, buttressed by a computer system and a team of attendance counselors to track and advise students, cut the school's absenteeism rate in half, from 36 percent in 1983 to 18 percent this year. That program became the model for the city-wide $2 million campaign against truancy.

The impact on test scores was predictable, Williams said. "The more a student goes to school, the more he learns. How can a student who hasn't been in school half the year be able to perform well on these tests?"

But improving attendance was just part of his plan to "turn Cardozo around." Williams also worked at raising the expectations of students and teachers and established test-preparation and tutorial programs developed from years of educational research that he did as a doctoral candidate at George Washington University.

Raising the expectations of students who had become used to making failing grades and teachers who were more accustomed to disciplining students than teaching them was painstaking work, he said.

"When I got here, I said this would be an academic high school. I said it was going to be the best school in the city. I said it so often that the students started believing me and they started working hard to help me reach that goal," he said.

Every student in the school was involved in test-preparation and tutoring programs, which focused on specific skills measured on the test, such as vocabulary, reading comprehension and identifying parts of speech. Students who scored lowest on standardized tests in previous years were given special attention.

In addition, in every math, science, reading and social studies class, teachers were required to give students test questions every day.

Students who tested in the bottom 25 percent got the most attention, Williams said, "because we analyzed the test data and discovered that it's the ones in the bottom 25 percent of the school who are scoring as many as five and seven years below grade level and are dragging down the overall average for the entire school."

Test preparation and tutorial programs are not new at secondary schools, school officials said, but at Cardozo these tactics seemed to have worked well because of the orderliness and discipline that now typifies the atmosphere of the school. Williams said he has taught students that "discipline . . . is being able to control your emotions, to get to class on time, to do your homework, to cut the TV off and study, to go to bed on time. It's paid off for us. And we expect more success in the near future."