Figure 10.3 Geoprofile confidence intervals.
10.3.2 Performance
Table 10.1 presents information on crime patterns and CGT test results from the SFU serial murder data set, including number of crime sites, size of hunting and search areas, and hit score percentages (the implications of
© 2000 by CRC Press LLC
Table 10.1 Crime Site Patterns and CGT Results
|
Crime |
|
Area/Crime |
CGT Hit |
Search |
Serial Murderer |
Sites |
Hunting Area |
Site |
Score % |
Area |
|
|
|
|
||
|
Victim Encounter/Body Dump Sites |
|
|
||
Chase |
5 |
8.0 km2 |
1.6 km2 |
1.7% |
0.1 km2 |
DeSalvo |
14 |
1256 km2 |
89.7 km2 |
17.8% |
223 km2 |
Ramirez |
21 |
6393 km2 |
304 km2 |
9.8% |
625 km2 |
Berkowitz |
10 |
816 km2 |
81.7 km2 |
4.7% |
38.2 km2 |
|
|
Victim Encounter Sites |
|
|
|
Olson |
15 |
299 km2 |
20.0 km2 |
3.0% |
9.1 km2 |
Buono |
9 |
487 km2 |
54.1 km2 |
9.4% |
45.6 km2 |
Bianchi |
|
|
|
3.2% |
15.6 km2 |
Collins |
7 |
62.6 km2 |
8.9 km2 |
1.1% |
0.7 km2 |
Dahmer |
10 |
6.8 km2 |
0.7 km2 |
8.7% |
0.6 km2 |
Brudos |
6 |
5726 km2 |
954 km2 |
2.2% |
128 km2 |
|
|
Body Dump Sites |
|
|
|
Olson65 |
11 |
14,262 km2 |
1,297 km2 |
12.5% |
1779 km2 |
Buono and Bianchi |
9 |
305 km2 |
33.94 km2 |
9.2% |
28.0 km2 |
Sutcliffe Res 1 |
20 |
9547 km2 |
477 km2 |
4.9% |
465 km2 |
Res 2 |
|
|
|
2.4% |
232 km2 |
Rifkin |
16 |
25,278 km2 |
1580 km2 |
7.2% |
1829 km2 |
Collins66 |
7 |
368 km2 |
52.54 km2 |
23.8% |
87.6 km2 |
Wuornos Body |
6 |
16,980 km2 |
2830 km2 |
3.8% |
643 km2 |
Vehicle |
7 |
14,970 km2 |
2139 km2 |
5.4% |
813 km2 |
65The hit score percentage and search area for Agassiz Mountain Prison was 2.5% (352 km2); aspects of the case suggest this location was a significant offender anchor point.
66The hit score percentage and search area for Eastern Michigan University was 15% (55.3 km2); aspects of the case suggest this location was a significant offender anchor point.
which are discussed below). Case data are divided into victim encounter/body dump (i.e., there was no victim transport), victim encounter, and body dump sites. A minimum of five different locations of the same crime site type connected to a single residence was necessary for a site type to be individually analyzed (see Rossmo, 1995a, for full study details). Table 10.2 shows the comparative CGT hit score percentages for those cases where more than one type of crime site was available for examination. Generally, encounter sites result in lower hit scores than body dump sites, though in some cases best performance is achieved from the use of all site types (optimal crime site selection in geographic profiling is discussed below).
© 2000 by CRC Press LLC