From Deadly Lessons:
Figure 9-4 shows that student-perpetrated school rampages (with or without a fatality) are not entirely new phenomena. There were two such incidents in the 1970s and six in the 1980s. And yet it also seems clear that the frequency of student-perpetrated school rampages resulting in multiple victimizations increased dramatically after 1994. The difference is highlighted in the figure by lines showing the mean number of such incidents per year in the 17-year period from 1974 to 1990 and the 11-year period from 1991 to 2001. The mean number of student-perpetrated rampages increased from an average of 0.53 incidents per year to an average of 3.27 incidents per year.
It is important to note that these are very small numbers. It is also important to note that the increase observed in the 1990s could be explained at least in part by a reporting phenomenon. It seems likely that the media would cover fatalities in schools, and particularly fatalities that occurred with multiple victimization, with a high degree of consistency and reliability over the entire period from 1974 to 2001. What we cannot be sure of, however, is whether the media would have covered incidents involving multiple victimizations without a fatality as consistently or reliably over this period. While it seems likely that multiple victimizations in a school setting would be newsworthy throughout this period, we cannot be entirely sure that the media weren’t particularly sensitized to the issue of school rampage shootings in the late 1990s, and therefore began covering these more assiduously (even when they did not involve fatalities) than had previously been true. If the media were sensitized to these events, part of the increase could be accounted for by the increased likelihood of news accounts of such events, not by an increase in the real underlying rate of these events. Still, the difference in the rate of these events is impressive and would easily be rejected as a chance occurrence if the reporting were accurate, even though the numbers are very small.
Our media search also uncovered five student-perpetrated school rampages in other countries (Table 9-2). While these results may be biased by the less certain coverage of international events, it seems noteworthy that only one incident occurred in 1975 and no additional shootings occurred until 1999. The 1999 shooting was followed by three other rampages involving different means of inflicting harm on others (arson, stabbing, and shooting). This suggests that school rampages are not unique to the United States and, since no international school rampages were evident until 1999, rampages in other countries may have been somehow influenced by the U.S. epidemic in the 1990s.
One final point: a December 2001 article in the Boston Globe reported that since the April 1999 Columbine tragedy, 12 U.S. school rampage shootings have been discovered and thwarted before they came to fruition. Ideally, we could put these events on Figure 9-4 as a further indication of the trends in time of these school rampage shootings. There are three problems in doing so, however. First, it is quite likely that, given the public concern about the school rampages, the newspapers would be much more likely to report on thwarted incidents in this period than they would have in earlier periods. Second, given efforts to mobilize students to report these events and law enforcement to take them seriously, it is quite likely that the police would find more such events and that they would treat each event as a serious plot that was really to be carried out rather than mere fantasizing by the kids involved. Third, in any case, Figure 9-4 records events that actually occurred. Presumably, for every act that actually occurred, there were some others in which some preparations were made, but for a variety of reasons, the act never occurred. Consequently, we would have to assume that there were even more attempts to be found than completions. What we are observing in the thwarted events, then, are some incidents that might never have occurred even if the police had not found them in time.
For all these reasons, it is inappropriate to put these thwarted shootings in the same figure as the other data. Still, the fact that these thwarted events were planned during this period is consistent both with the idea that planning for such events increased in the latter half of the 1990s, and that society and the police got a bit better at learning about and thwarting the events. But the data cannot prove this claim.
While the data depicted in Figure 9-4 are weak by scientific standards, they are still important to include in the effort to understand multiple-victim lethal school violence. What they suggest is that school rampage shootings are not a recent phenomenon, nor are they uniquely a U.S. phenomenon. It seems likely that the United States has experienced an epidemic of these incidents in the latter half of the 1990s—that is, an unexpected increase in their number. There may also have been some contagion mechanisms at work—that is, some kind of copycat influence.
If the international and thwarted incidents are included in the basic time trend of observed school rampages, then copycat mechanisms seem likely. But there also seems to have been a small previous increase in these incidents in the late 1980s that no one much noticed. The lack of notice may have prevented the escalation of these shootings through the copycat phenomenon. But this is largely speculation, not a scientific claim. It seems unlikely that this phenomenon is either entirely new or entirely unique to the United States. It may have gotten worse recently and— even more speculatively—that may be in part the result of a kind of contagion. But the problem has endemic and international aspects as well as epidemic and U.S. ones.