BLOOMINGTON, Ind.  —  Strict zero-tolerance disciplinary codes do not necessarily create safer schools for children and teachers, a study released Wednesday said.

The study by the Indiana Education Policy Center also found that expelling children under zero-tolerance policies does not change student behavior, that minority students are unfairly singled out as violators, and that zero-tolerance policies can increase high school dropout rates.

The findings generally agreed with those from other national reviews of zero-tolerance policies.

"Zero tolerance is a political response, not an educational sound solution," said Rba, director of the Safe and Responsive Schools Project at Indiana University, where the policy center is located.

At least one Indiana Department of Education official defended the practice, however.

"We know that when it is used in a way to prevent serious crimes and applied evenly and equitably, it works and works well," said William Modzeleski, director of the department's Safe and Drug-Free Schools Program.

Zero-tolerance policies generally target drug and alcohol use, the display of weapons or use of violence or threats. Offenses under those categories are treated equally and are severely punished, often with expulsion, Skiba said.

"Punishment is only effective if it changes behavior," Skiba noted. "Some of the results suggest that suspension may act more as a reward for some students."

The 22-page study cites numerous examples, including a New Jersey second-grader who was expelled for drawing a picture of gun and a Pensacola, Fla., honor student who was suspended for 10 days for possessing nail clippers that included a filing implement.

The most-discussed Indiana case involved a gifted 15-year-old female violinist who was suspended for a semester in 1996 for taking a Swiss army knife to school to trim violin strings. A court upheld the school's action.

Such cases have prompted educators to re-examine the effectiveness of zero-tolerance policies, said Paul Houston, executive director of the American Association of School Administrators.

"Zero tolerance also means zero judgment for officials, and I raise that warning flag whenever I speak about it," Houston said. "When you dole out a one-size-fits-all policy, there will be a lot of issues that come up where you look foolish or fail to correct the behavior you were addressing."

In Indiana, school officials have attended state-sponsored safety academies to train them how to address infractions, said Cathy Danyluk, school safety specialist for the education department.

The IU study concludes that although zero tolerance is flawed, it does have a use in the most serious cases.

"Our best knowledge suggests that schools are more likely to be able to reduce their chance of violence by putting in place preventive programs," Skiba said. "We assume that we need zero tolerance because prevention takes too long to work."