When a Howard County judge last week asked Patty Ann Newman why she missed 85 days of school last year and seven of 10 summer classes in July, the 15-year-old Savage, Md., resident offered a simple explanation.

"I just didn't want to go," Newman told District Court Judge Diane G. Schulte, who then ordered Newman's mother jailed overnight for her failure to ensure Patty's attendance at Waterloo Middle School.

The jailing of Virginia Newman, 50, for 16 hours Tuesday made her the third known case of a Maryland parent imprisoned for violating the state's compulsory school attendance law--and touched off a debate in educational and legal circles about the rights and responsibilities of parents and children and the role of courts in handling chronically truant students.

Schulte's ruling was hailed by Howard school officials who say her and other judges' tough approach to truancy has sharply reduced the number of such cases in the past two years.

Other educators and an outspoken juvenile court judge in neighboring Prince George's County, however, expressed misgivings about the effectiveness of jailing parents whose children repeatedly skip school.

"One has to be very, very certain that there's a blatant disregard for the attendance law before going to a court for help," said E. Lloyd Robertson, the director of pupil services in Calvert County, where the parents of a truant 14-year-old boy were briefly jailed in the late 1970s.

"In that case, I found the parents didn't perceive that an education was important," and their son spent his days working on neighbors' tobacco farms, Robertson said. "The funny thing was, he seemed to have a desire to learn things. He enjoyed school."

Not so with thousands of other truants, according to officials in the Maryland state education department. "Sometimes it's the home environment or a problem the youngster himself has," said Mary K. Albrittain, the state pupil services director. "But it can also be the program, something a school doesn't have that would keep a student interested."

Albrittain, whose office just concluded its first statewide survey of chronic truancy cases, said that more than 6,600 of Maryland's 332,000 high school students are "hard core" truants, teen-agers for whom counseling and special programs apparently have failed. In the past five years, local school officials referred more than 160 of those cases to district courts, the survey found.

In Wicomico County alone, the district court heard 125 truancy cases since 1978, according to the survey; district courts in Howard, Prince George's, Anne Arundel and Calvert heard 43. No figures were available for Montgomery County, which refers its truancy cases to juvenile court. But Jane S. Witt, the regional administrator for the state Juvenile Services Administration, said Montgomery's 20 juvenile probation officers each has a 40-person caseload.

In nearly all of those cases, the truancy problem is compounded by delinquency or other "brushes with the law." In the case of the older truants, drugs and alcohol are often part of the picture, state and local officials said.

Montgomery officials said they are able to help keep a lid on the truancy problem in part by prompt phones calls to parents when their children are reported absent. In addition to the work of 28 pupil personnel workers, the county school system controls truancy with a requirement that any student with 20 or more unexcused absences in a year must repeat that grade, official said.

"It's very rare for a truancy case to get to court here," said Bill E. Myer, a 23-year veteran of Montgomery schools who now supervises the county's office of interagency and alternative programs. "There is very little that the courts can do. And the juvenile court system really can't do anything without the parents' help."

Myer, who is executive director of the 500-member International Association of Pupil Personnel Workers, an organization of truancy experts, said that in most cases truancy "is a sign that a parent has lost control."

"No school system is immune to the problem of truants," said Myer. "In fact, nowadays you see a lot of systems shifting their focus from secondary to middle schools--to get to the trouble kids even earlier."

In Howard County, where the number of truancy cases dropped from 363 to 242 between the 1981 and 1982 school years, school officials have launched Project LIFE (Looking Into Future Experiences) to curb truancy among ninth graders. "Truancy is one prime indicator that something is wrong with a student," said Sharon Johnson, Howard's pupil services director.

Patty Newman, who turned 15 earlier this month, said she started " 'hooking' class" after run-ins with school administrators over her behavior in class and the subsequent suspension.

When she skipped school, she would usually sleep until noon, stay at home to watch television, go to friends' houses or spend the day at shopping malls in nearby Laurel, she said. That routine, she added, was "funner than going to class."

"My mom can't pull me by the ears and force me to stay on school," Newman said. "Mom has a little part in it, but I guess I'm responsible for going or not going."

Newman, who hopes one day to be a truck driver, said she never took the threat of a jail term for her mother seriously because classmates' parents had only been fined when their children skipped.

She had high praise for one teacher and a counselor at her school and said she enjoyed some subjects. "I don't mind school as long as I get along with my teacher," she said. She added that she intends to attend classes regularly at Hammond High School this fall.

"What we do with a ninth grader who skips school may have a lot to do with how he or she does in high school and later on in life," said Johnson, who called the decision in the Newman case and recent heavy fines against two other truants' parents "extremely powerful tools" in resolving cases where parents took little interest in their child's education.

However, in those cases where parents have tried--and failed--to keep a truant in school, a court has virtually no power to intercede, according to Prince George's Circuit Court Judge Vincent J. Femia.

"Nobody gives a damn about truants," declared Femia, who spent three of his six years on the bench as a full-time juvenile court judge. "They're the throwaways of our society, but the tragedy is that the law has divested the court, the government and parents of the power to deal with these kids properly.

"And what are we saying when we put a parent in jail? 'OK, you failed with your kid, so now go to jail.' "

Femia recalled one case involving a mother who each day would drive her daughter to school and escort her to class. The daughter would wait until her mother left--and then leave school herself, Femia said.

"This poor woman begged the court for help," said Femia, the father of two teen-agers. "I told her that, legally, there was nothing I could do." Under Maryland law, habitual truants designated "children in need of supervision" by the state may not be placed in detention, state mental hospitals or confined with delinquent children--unless they too are delinquent, Femia said.

"A court's power is illusory," said Femia. "It works only with the threat that a person will be deprived of something. We should tell habitual truants they face permanent expulsion from school--for life. Either that, or establish a facility where they can be confined or treated."