Using two publications about fatal stabbings, one being “Murder By Stabbing” (A.C. Hunt) and “Patterns of Stab Wounds: A Six Year Study” (D.A. Rouse), I derived a formula for the probability distribution of number of stab wounds by fitting the data to a Zipf distribution. When a range of stab wounds was given rather than a precise point value, I used a midpoint estimate before feeding the data to the regression program. Here first the tables that can be found in the publications.

“Murder By Stabbing” (A.C. Hunt, n = 100 victims)

Number of Stab Wounds | Incidence among Fatal Cases |

1 | 38 % |

2-10 | 35 % |

11-20 | 14 % |

21-30 | 6 % |

> 30 | 8 % |

“Patterns of Stab Wounds: A Six Year Study” (D.A. Rouse, n = 152 victims)

Number of Stab Wounds | Incidence among Fatal Cases |

1 | 44 % |

2 | 13 % |

3 | 9 % |

4 | 5 % |

5 | 1 % |

6 | 7 % |

7 | 3 % |

8 | 3 % |

9 | 4 % |

10 | 1 % |

11-20 | 6 % |

21-30 | 3 % |

31-40 | 1 % |

> 40 | 1 % |

Fitting both and then calculating the average of the constants, linearly weighted by study size, leads to the following formula for the expected share p of fatal cases in which n stab wounds are observed:

p = 40 / n^1.4

I rounded the constants liberally as one should not expect high precision from such small samples. I also checked whether an exponential fit might lead to a lower sum of squared residuals, however, the Zipf fit outperformed the exponential fit quite noticeably. Both from the table and the fit, one can see that fatal stabbings with a large number of wounds (overkill) are not as uncommon as one might suspect. In about 1 in 6 fatal stabbings the victim receives more than 10 wounds, in 1 in 12 stabbings more than 20 wounds, in 1 in 25 stabbings more than 30 wounds and in roughly 1 in 100 stabbings even more than 40 wounds.

Unsurprisingly, a comparison to data from non-fatal stabbings shows that a larger number of wounds are more common in fatal stabbings than in non-fatal ones. Here is the incidence of stab wounds in non-fatal stabbings, taken from “The Differences in Stabbing-Related Injury Profiles of Men and Women” (Michael Rozenfeld), a large Israeli sample of n = 9173 non-fatal stabbings, compared to what the above two studies found for the fatal cases:

Number of Stab Wounds | Non-Fatal Stabbings | Fatal Stabbings |

1-2 | 87 % | 55 % |

3+ | 13 % | 45 % |

Unfortunately, the Israeli study does not allow a better breakdown, but one can clearly see that cases with three or stab wounds are much more frequent in cases with fatal outcomes. In a later post I want to go more into the site of the stab wounds as well as defense wounds, but for now, I will leave it at mentioning that the chest is the most common site for stab wounds, being the target (or one of the target sites) in about 50 % of non-fatal and 75 % of fatal cases. In a series of 14 stabbing videos I recently watched, the chest was also the most common site for the initial stab wound (7 out of 14 cases), followed by the abdomen (5 out of 14) and back (2 out of 14).

[…] recently analyzed the distribution of number of stab wounds in fatal stabbings, I also wanted to have a look at whether there are any gender differences. The limited data implies […]

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[…] been recently reading literature and writing blog entries on stabbings (see here, here and here) and that brought me to watching videos of fatal stabbings via Kaotic. I did a […]

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