The principle of “zero tolerance” is to some extent self-explanatory, but there is no universally accepted definition. The American Heritage Dictionary defines zero tolerance as “[t]he policy or practice of not tolerating undesirable behavior, such as violence or illegal drug use, especially in the automatic imposition of severe penalties for first offenses.” Skiba points out that the typical definitions of zero tolerance emphasize “punishing a range of behaviors, both major and minor, equally severely.” The National Center for Education Statistics in the United States defines a zero tolerance policy as “a school or district policy that mandates predetermined consequences or punishments for specific offences.” Gabor found that most participants in his research on school violence and zero tolerance in Canada defined it as “marking out clear lines for acceptable behaviour, along with repercussions for violating the limits.”
Although the Ontario government promised “zero tolerance” for bad behaviour in schools before the Safe Schools Act was enacted, and the Act prescribes “mandatory” suspensions and expulsions, the presence of mitigating factors in the current legislation precludes it from being strictly characterized as “zero tolerance”. Likewise, although the TDSB Safe Schools Foundation Statement Policy speaks of “zero tolerance” and “mandatory” suspensions and expulsions, the direction to principals and teachers to apply mitigating factors in disciplinary matters precludes it from being strictly characterized as “zero tolerance”. The real issue is whether there is a practice of “zero tolerance”. At least one group of experts on school violence in Canada takes the position that zero tolerance can, in fact, only exist as a practice:
In our view, zero tolerance is neither a policy nor a program, but a practice. It is the establishment of a specific consequence (or range of consequences) for a specific infraction and the consistent application of that consequence. In other words, in any disciplinary situation, if an act has a specific and inevitable consequence, then zero tolerance is being practised. For example, possession of a knife in school results in a five-day suspension. If this act is always treated in the same way, zero tolerance is being practiced. No deviation in consequence is allowed. Zero tolerance has recently come to be interpreted as a policy which provides a suspension/expulsion consequence in response to violations of the policy, i.e., absolute disciplinary outcomes. We take the position that zero tolerance is practised when the absolute inevitability of a consequence is present, irrespective of what that consequence may be.
In assessing whether zero tolerance is being practiced in the school system in Ontario, it is important to keep in mind that principals and teachers are receiving two contradictory messages, one advocating “zero tolerance” and prescribing “mandatory” action and the other directing them to apply mitigating factors.
 The American Heritage Dictionary of the English Language, 4th ed. (Boston: Houghton Mifflin, 2000).
 R. Skiba, Zero Tolerance, Zero Evidence: An Analysis of School Disciplinary Practice, Indiana Education Policy Center, 2000, p. 3 (fn. 1). See Appendix I, Tab 31. Online at: http://www.indiana.edu/~safeschl/ztze.pdf.
 U.S. Department of Education, National Center for Education Statistics, Violence and Discipline Problems in U.S. Public Schools: 1996-97 (Washington D.C.: U.S. Government Printing Office, 1998), 18. Online at: http://nces.ed.gov/pubs98/98030.pdf.
 Supra note 21 at 5.
 D.M. Day, Golench, C.A., MacDougall J. & C.A. Beals-Gonzalez, School-Based Violence Prevention in Canada: Results of a National Survey of Policies and Programs (Ottawa: Supply and Services Canada, 2002), 41 (fn. 2). See Appendix I, Tab 48.