...recent research indicates a negative relationship between the use of school suspension and expulsion and schoolwide academic achievement, even when controlling for demographics such as socioeconomic status... it becomes difficult to argue that zero tolerance creates more positive school climates when its use is associated with more negative achievement outcomes.
...Rather than reducing the likelihood of disruption, however, school suspension in general appears to predict higher future rates of misbehavior and suspension among those students who are suspended
What has been the impact... of zero tolerance policies on students, families, and communities?
...concern has been raised in the literature that zero tolerance policies may create, enhance, or accelerate negative mental health outcomes for youth by creating increases in student alienation, anxiety, rejection, and breaking of healthy adult bonds. Preliminary estimates suggest that the extensive use of suspension and expulsion and the increased reliance on the juvenile justice system for school misbehavior may not be cost effective. Finally, there is a strong body of evidence showing that preventing or treating delinquency and school failure are more cost effective than doing nothing or paying welfare and prison costs incurred by under-educated and alienated youth...
It is of even greater concern that the overwhelming majority of findings from the available research on zero tolerance and exclusionary discipline tend to contradict the assumptions of that [zero tolerance] philosophy.
...Youth Offender Program... mandated consequences for first time juvenile offenders, and at the same time, provided counseling, mediation, conflict resolution, and community service, rather than incarceration in the local youth detention facility. The program was called "Making a Difference." Cases involving non-violent offenders were referred... to the AYC for adjudication. The program was very successful. Students benefited from the counseling and other supports... and in most instances they did not repeat the offenses and they did better in school.
...Skiba said... suspension itself appears to contribute to later trouble with the law. Take similar kids at similar schools who commit similar offenses. Suspend some but not others. The ones who are suspended are more likely to get suspended again, to drop out, and to get arrested.
"The theory was that by providing severe consequences to even minor infractions, it would send a message to students that disruptive behavior was unacceptable," Skiba said.
An American Psychological Association task force issued a report on zero tolerance in 2008 that said, "Rather than reducing the likelihood of disruption... school suspension in general appears to predict higher future rates of misbehavior and suspension among students who are suspended."
The report also looked at the assumption that removing disruptive students would lead to a safer climate at school. "Although the assumption is strongly intuitive," the report said, "data on a number of indicators of school climate have shown the opposite effect, that is, that schools with higher rates of suspension and expulsion appear to have less satisfactory ratings of school climate."