Most violent dates 1998-2007:
| Date | Homicides |
|---|---|
| 2000-Jan-01 | 93 |
| 1998-Dec-25 | 92 |
| 2001-Jan-01 | 89 |
| 1999-Jan-01 | 88 |
| 2005-Jan-01 | 80 |
| 1999-Dec-25 | 78 |
| 1998-Mar-01 | 76 |
| 1998-Jun-14 | 74 |
| 1998-Oct-25 | 73 |
| 1998-Nov-29 | 73 |
Six of the ten most violent days from 1998 to 2007 where either the first day of the year or Christmas. To check whether holidays were really more violent than the rest of the year I plotted the total number of homicides for the period 1998-2003, and 2005 (so each day after February would fall exactly once each day of the week). I excluded the drug war years to make the pattern more obvious.
| Total Homicides (Sum of All Dates) | Day Number | Holiday |
|---|---|---|
| 558 | Jan-01 | New Year |
| 388 | Dec-25 | Christmas |
| 357 | Sep-16 | Independence Day |
| 281 | Nov-02 | Day of the Dead |
| 270 | Feb-15 | Day After Valentine’s Day |
| 270 | Dec-12 | Virgin of Guadalupe |
| 269 | Dec-24 | Christmas Eve |
| 263 | May-10 | Mother’s Day |
| 259 | Dec-31 | New Year’s Eve |
| 256 | May-03 | Related to Labor Day? |
I find it quite interesting that the day of the dead would be one of the most violent days of the year. In countries where most homicides are solved, most homicide victims knew their attacker, so perhaps hanging out with family and friends during the holidays is not such a good idea? Does that stress people out?
Performing an analysis of variance and testing for multiple comparisons with a Tukey test, the list of holidays above (coded as a binary variable), controlling for month of year and day of week, were expected to have between 28 and 39 extra homicides with a point estimate of 33 homicides.
Results for all days from 1998 to 2007:
## Tukey multiple comparisons of means ## 95% family-wise confidence level ## ## Fit: aov(formula = total.deaths ~ as.factor(holiday) + as.factor(month(date)) + as.factor(wday), data = homicides) ## ## $`as.factor(holiday)` ## diff lwr upr p adj ## TRUE-FALSE 33.46 28.37 38.55 0 ## ## $`as.factor(wday)` ## diff lwr upr p adj ## 2-1 -11.9148 -13.3360 -10.49355 0.0000 ## 3-1 -16.9419 -18.3645 -15.51927 0.0000 ## 4-1 -18.3969 -19.8188 -16.97494 0.0000 ## 5-1 -17.6014 -19.0226 -16.18016 0.0000 ## 6-1 -16.3855 -17.8068 -14.96427 0.0000 ## 7-1 -11.1132 -12.5344 -9.69192 0.0000 ## 3-2 -5.0271 -6.4490 -3.60516 0.0000 ## 4-2 -6.4821 -7.9033 -5.06083 0.0000 ## 5-2 -5.6866 -7.1072 -4.26605 0.0000 ## 6-2 -4.4707 -5.8913 -3.05016 0.0000 ## 7-2 0.8016 -0.6189 2.22219 0.6398 ## 4-3 -1.4550 -2.8776 -0.03238 0.0411 ## 5-3 -0.6595 -2.0815 0.76240 0.8188 ## 6-3 0.5564 -0.8656 1.97829 0.9109 ## 7-3 5.8287 4.4068 7.25064 0.0000 ## 5-4 0.7955 -0.6258 2.21670 0.6489 ## 6-4 2.0113 0.5901 3.43259 0.0006 ## 7-4 7.2837 5.8625 8.70495 0.0000 ## 6-5 1.2159 -0.2047 2.63645 0.1506 ## 7-5 6.4882 5.0677 7.90880 0.0000 ## 7-6 5.2724 3.8518 6.69292 0.0000Sunday is 1