15 Multiple victim Public Shootings long delays before execution and its over-inclusiveness (i.e, the variable measures the execution rate for all murders not mass murders), so we also tried including a simple dummy variable for whether the dead penalty was in effect. However, the coefficient was never statistically significant and did not alter our other results Finally, the law variable denoting the imposition of additional penalties for using a gun in a crime is insignificant. The impact of the death penalty on public shootings stands in sharp contrast to evidence that we have put together on murder rates using county level data from 1977 to 1995. We find that a one percentage point increase in the execution rate is associated with a seven percent decline in the overall murder rate and the effect is statistically significant at better than. 01 percent level. The question is why does the presence of concealed handgun laws deter multiple victim shootings when other penalties fail to have an effect. One possibility is that the execution rate does not deter mass public killers because they already die at such high rates from crime, but concealed handgun laws deter attacks because killers are committing the crime to kill or injure a large number of people and that their return from these attacks is reduced when citizens with concea led handguns can limit the carnage. We also reestimated the regressions by including both the murder and total bombing rates as explanatory variables because there may be some overlap between factors that explain public shootings, overall murders and bombings that are not taken into account by the independent variables in the previous regressions. Adding these variables to the regressions in Tables 6, 7 and 8 produces little change from our previous results. In 17 of the 18 regressions, the shall issue variable has a negative and statistically significant effect on multiple shootings. 22 Iv. Alternative Measures of Multiple Shootings 22 Even in the one case where the coefficient is no longer statisticall significant it is still negative. The t-statistic is -1.63 in the regression on injuries per 100,000 persons using the specification in Table 6 with the addition of the murder and bombing variables. The murder rate is always positively related to mass shootings but statistically significant in only six of the 18 regression equations. Total bombings are never statistically significant In any
15 Multiple Victim Public Shootings long delays before execution and its over-inclusiveness (i.e., the variable measures the execution rate for all murders not mass murders), so we also tried including a simple dummy variable for whether the dead penalty was in effect. However, the coefficient was never statistically significant and did not alter our other results. Finally, the law variable denoting the imposition of additional penalties for using a gun in a crime is insignificant. The impact of the death penalty on public shootings stands in sharp contrast to evidence that we have put together on murder rates using county level data from 1977 to 1995. We find that a one percentage point increase in the execution rate is associated with a seven percent decline in the overall murder rate and the effect is statistically significant at better than .01 percent level. The question is why does the presence of concealed handgun laws deter multiple victim shootings when other penalties fail to have an effect. One possibility is that the execution rate does not deter mass public killers because they already die at such high rates from their crime, but concealed handgun laws deter attacks because the killers are committing the crime to kill or injure a large number of people and that their return from these attacks is reduced when citizens with concealed handguns can limit the carnage. We also reestimated the regressions by including both the murder and total bombing rates as explanatory variables because there may be some overlap between factors that explain public shootings, overall murders and bombings that are not taken into account by the independent variables in the previous regressions. Adding these variables to the regressions in Tables 6, 7 and 8 produces little change from our previous results. In 17 of the 18 regressions, the shall issue variable has a negative and statistically significant effect on multiple shootings.22 IV. Alternative Measures of Multiple Shootings 22 Even in the one case where the coefficient is no longer statistically significant it is still negative. The t-statistic is –1.63 in the regression on injuries per 100,000 persons using the specification in Table 6 with the addition of the murder and bombing variables. The murder rate is always positively related to mass shootings but statistically significant in only six of the 18 regression equations. Total bombings are never statistically significant in any of these regressions
Chicago Law and Economics Working Paper The dependent variable in Table 9 is the number of multiple shootings reported in the first section of the New York Times. Because the Tobit regressions with state specific effects did not converge, we substituted regional dummy variables in the Tobit gressions. We also present Ols estimates that include state fixed ffects variables. Regional and even state fixed effects may be important if the New York Times has a regional or state bias in its coverage of shooting events. Overall, the results are consistent with our earlier findings. Both the dummy shall issue law variable and the split time trend variables indicate significant reductions in multiple shootings after the passage of the law. The Ols estimates also produce negative effects of the law but these estimates are less significant (i.e. they are generally significant at the. 10 but not.05 level) The only other study that we know of on multiple victim murders defines the offense more narrowly than we have and it limits the definition to four or more people killed in the shooting (Petee et. al, 1997). This definition sharply lowers the number of public shootings to 36 incidents during the 1977-1995 period. W attempted to explain both the per capita and absolute number of people killed in these shootings using the same specifications as in Tables 6 and 7. 23 The results are similar to those reported earlier We find that shall issue laws reduce the number of deaths and that these deaths were increasing before passage of the law and falling thereafter 23 Again, the Tobit estimates do not converge when state fixed effects are used for there is not enough variation in the data to distinguish the law's impact on these shootings with state fixed effects. Consequently, the state fixed effects are replaced with regional dummies(Northeast, Midwest, South, and West(the left 24 In explaining the per capita number of people killed, the shall issue concealed handgun dummy variable was- 1207502(t-statistic 1.966)and the difference in the before and after trends equaled -057(f-statistic =6.96). For the regressions explaining the number of people killed in a state, the shall issue concealed handgun dummy variable was-154(t-statistic =2.363)and the difference in the before and after trends equaled -705(f-statistic = 9.41). The mean number of deaths per 100,000 persons per state per year is .0037 (standard deviation =0294)and the mean number of deaths per state per year is 249(standard devia
Chicago Law and Economics Working Paper 16 The dependent variable in Table 9 is the number of multiple shootings reported in the first section of the New York Times. Because the Tobit regressions with state specific effects did not converge, we substituted regional dummy variables in the Tobit regressions. We also present OLS estimates that include state fixed effects variables. Regional and even state fixed effects may be important if the New York Times has a regional or state bias in its coverage of shooting events. Overall, the results are consistent with our earlier findings. Both the dummy shall issue law variable and the split time trend variables indicate significant reductions in multiple shootings after the passage of the law. The OLS estimates also produce negative effects of the law but these estimates are less significant (i.e., they are generally significant at the .10 but not .05 level). The only other study that we know of on multiple victim murders defines the offense more narrowly than we have, and it limits the definition to four or more people killed in the shooting (Petee et. al., 1997). This definition sharply lowers the number of public shootings to 36 incidents during the 1977 - 1995 period. We attempted to explain both the per capita and absolute number of people killed in these shootings using the same specifications as in Tables 6 and 7.23 The results are similar to those reported earlier. We find that shall issue laws reduce the number of deaths, and that these deaths were increasing before passage of the law and falling thereafter.24. 23 Again, the Tobit estimates do not converge when state fixed effects are used for there is not enough variation in the data to distinguish the law's impact on these shootings with state fixed effects. Consequently, the state fixed effects are replaced with regional dummies (Northeast, Midwest, South, and West (the left out region)). 24 In explaining the per capita number of people killed, the shall issue concealed handgun dummy variable was -.1207502 (t-statistic = 1.966) and the difference in the before and after trends equaled -.057 (f-statistic = 6.96). For the regressions explaining the number of people killed in a state, the shall issue concealed handgun dummy variable was -15.4 (t-statistic = 2.363) and the difference in the before and after trends equaled -7.05 (f-statistic = 9.41). The mean number of deaths per 100,000 persons per state per year is .0037 (standard deviation = .0294) and the mean number of deaths per state per year is .249 (standard deviation = 1.52)
Multiple victim Public Shootings V. The Number of Shootings and the Number of People Killed or Injured Per Shooting The presence of concealed handguns should reduce both the number of public shootings and the amount of harm caused by any one event. Consider the following examples. During a recent shooting spree at a public school in Pearl, Mississippi, an assistant principal retrieved his gun and physically immobilized the shooter before he caused additional harm(cnn, october 2, 1997, 2: 40 PM EST). And in the public school related shooting in Edinboro Pennsylvania, which left one teacher dead, a shot gun pointed at offender while he was reloading his gun prevented additional harm (Reuters Newswire, April 26, 1998). The police did not arrive for another ten minutes. The examples mentioned in the introduction also illustrate cases where shooters have been shot by citizens and thus presumably prevented from harming even more peopl Although one can also imagine circumstances where shall issue law increase the availability of guns to potential offenders or where guns used in self defense lead to more not less killings. our results so far strongly indicate that these effects, if they exist, are not sufficient to offset the overall negative impact of shall issue laws on multiple shootings Here we separate the effects these laws have on the number of shootings from the number of people harmed. Suppose, for example, perpetrators are undeterred by legal penalties or the prospect of encountering an armed defender. Then the number of persons harmed per shootings could still fall(as the two school shooting examples suggest) if concealed handguns interfered with the offender's ability to carry out his plans. Using either the dummy law variable or the before-and-after time trends the coefficients in table 0 indicate that concealed handguns reduce both the number of shootings and the number of people harmed. 25 The evidence on whether shall issue laws have a bigger impact on the number of 25 Note that there are 234 observations in the deaths or injuries per shooting regressions although Table 1 indicates that there were 396 shootings in the sample period. The dependent variable in equations (1)-(3)in Table 10 equals the average number of deaths or injuries per shooting in a state in a year Hence if there were two or more multiple shootings in a state in a year, this counted as one observation in the regression
17 Multiple Victim Public Shootings V. The Number of Shootings and the Number of People Killed or Injured Per Shooting The presence of concealed handguns should reduce both the number of public shootings and the amount of harm caused by any one event. Consider the following examples. During a recent shooting spree at a public school in Pearl, Mississippi, an assistant principal retrieved his gun and physically immobilized the shooter before he caused additional harm (CNN, October 2, 1997, 2:40 PM EST). And in the public school related shooting in Edinboro, Pennsylvania, which left one teacher dead, a shot gun pointed at offender while he was reloading his gun prevented additional harm (Reuters Newswire, April 26, 1998). The police did not arrive for another ten minutes. The examples mentioned in the introduction also illustrate cases where shooters have been shot by citizens and thus presumably prevented from harming even more people. Although one can also imagine circumstances where shall issue laws increase the availability of guns to potential offenders or where guns used in self defense lead to more not less killings, our results so far strongly indicate that these effects, if they exist, are not sufficient to offset the overall negative impact of shall issue laws on multiple shootings. Here we separate the effects these laws have on the number of shootings from the number of people harmed. Suppose, for example, perpetrators are undeterred by legal penalties or the prospect of encountering an armed defender. Then the number of persons harmed per shootings could still fall (as the two school shooting examples suggest) if concealed handguns interfered with the offender’s ability to carry out his plans. Using either the dummy law variable or the before-and-after time trends, the coefficients in Table 10 indicate that concealed handguns reduce both the number of shootings and the number of people harmed.25 The evidence on whether shall issue laws have a bigger impact on the number of 25 Note that there are 234 observations in the deaths or injuries per shooting regressions although Table 1 indicates that there were 396 shootings in the sample period. The dependent variable in equations (1) – (3) in Table 10 equals the average number of deaths or injuries per shooting in a state in a year. Hence if there were two or more multiple shootings in a state in a year, this counted as one observation in the regression