Teenagers run a greater risk of being robbed, assaulted or otherwise becoming victims of violence while they're in school than at any other time.

Eleven per cent of the nation's 21 million secondary school students have something stolen from them at school each month - usually items valued at less than $10 that are taken from desks and lockers.

In a typical month, about 12 per cent of all secondary schools teachers have something stolen from them at school.

More than 25 per cent of all schools are vandalized in some way every month, with the average damage $81. In addition, 10 per cent of all schools are burglarized each month at an average cost of $183.

Those are statistics from a three-year study of school crime which Health, Education and Welfare Secretary Joseph A. Califano yesterday.

Califono said in a statement the problem of school crime "remains extremely serious," although the study found vandalism and violence little [WORD ILLEGIBLE] from 1971 to 1976, with some improvement in urban areas.

The study, conducted by HEW's National Institute of Education, found that larger communities tend to have greater problems with school violence. But large numbers of non-urban schools are affected as well, because 80 per cent of the nation's schools are in suburban or rural areas.

It also said there were more problems in areas where crime and violence were high outside the school, and that when such factors were taken into account there was no relationship between a school's ethnic-racial makeup and the risk of violence there.

Principals of secondary schools reported higher levels of crime than those in elementary schools, the reporter said. It also noted:

About 1.3 per cent of secondary school students are physically attacked in some way at school each month. About 4 per cent of those attacks require medical attention. The risk of minor attack is as great in rural areas as in urban areas.

About one-half of 1 per cent of all secondary school students have something taken from them by force, weapons or threats each month. Eighty-nine per cent of those robberies involve no injury to the victim, 2 per cent require a doctor's attention.

Schools are about 5 times more likely to be burglarized than stores, and the risk of school vandalism is about the same in rural areas as in urban areas.

School crime costs about $200 million a year.

Intense competition for grades or leadership positions seems to lower the amount of violence at a school while increasing the amount of vandalism.

"A firm, fair and consistent system for running a school seems to be a key factor in reducing violence."