These are difficult questions and there is no black and white answer that fits every situation. The good news is that school and police officials are getting much better at preventing high-profile tragedies. Youth behavior is even more difficult to predict. Adolescent behavior is, by its nature, experimental and fluctuating. Therefore, predictability of youth behavior is even more difficult than that of adults.
Adults tend to recognize radical, dramatic changes in youth behavior.
However, adults continue to have difficulty in recognizing smaller, incremental changes in youth behavior. Early intervention to prevent violent incidents is complicated further because so many people have pieces of information about a child, but the pieces rarely are put together to get the whole picture until after a crisis occurs. The majority of high-profile school violence offenses do not occur spontaneously. To the contrary, most involved some type of prior planning. Additionally, they typically stem from the culmination of a series of deteriorating events experienced by the offender.