On Thursday Police Minister Nathi Mthethwa presented the SAPS 2012/2013 national crime statistics. In his statement he listed the increases or decreases of various categories of crime in terms, not in absolute numbers, but in the rate or ratio per 100 000 of the population.
Thus he stated, for instance, that total sexual offences decreased by 0.4% and robbery in non-residential premises by 0.6%. He added that there had been an increase of 1.2% in aggravated robbery, 3.3% in residential burglary, 0.6% in commercial crime, and 3.6% in residential robberies.Mthethwa also stated that "we have witnessed a slight increase of 0.6%" in the murder rate.
In absolute terms however there were 16 259 murders in 2012/2013, 620 up from the 15 609 recorded in 2011/2012. This is a 4.2% increase. How then can the differential between a 0.6% increase in the murder rate be reconciled with this 4.2% increase in the total number of murders?
The short answer is, it can't.
One possible explanation is that the population of South Africa grew by 3.3% between 2011 and 2012. However, Statistics South Africa estimates that the population of South Africa only grew by 1.34% between 2011 and 2012 (see here.)
In fact, what seems to have happened is the following: The 2011/2012 crime statistics' ratios per 100,000 of the population were calculated using Stats SA's 2011 mid-year population estimate of 50 586 757. For the 2012/2013 crime statistics the SAPS worked out the ratios using the Stats SA estimate of a population of 52 274 945 in 2012. It then worked out the change in the ratios per 100 000 of the population between the two.
However, the differential between the 2011 StatsSA estimate used by the SAPS and the 2012 one is 1 688 188, an implausibly large 3.34% gap. This doesn't reflect a real change in the population, but rather an adjustment upwards in StatsSA's estimate of the population (presumably post-Census 2011). According to these adjusted estimates the population in 2011 was 51 579 548 - only 695 397 (or 1.35%) fewer than in 2012.
If one uses the updated population figures of StatsSA for 2012 and 2011 then the murder rate actually increased by 2.78% (not 0.6%). There was a 1.53% increase in the rate of sexual offences (not a decrease of 0.4%) and an increase of 1.30% in non-residential robberies (not a decrease of 0.6%). The rate of aggravated robbery was up 3.24% (not 1.2%), that of residential burglary by 5.33% (not 3.3%), commercial crime by 2.61% (not 0.6%), and residential robbery by 5.65% (not 3.6%).
The table below sets out the change in the number of crimes committed, in various categories, between 2011/12 and 2012/2013 - and then the change in the ratio per 100 000 of the population using the old Stats SA population estimates for 2011 versus the new ones.
Table 1: Changes in the crime rate in 2012/2013 using the old StatSA 2011 population estimates (used by the SAPS) vs changes in crime rate using new StatsSA 2011 population estimates:
Crime Category |
2011/ 2012 |
2012/ 2013 |
Change in absolute numbers |
% change in absolute numbers |
Change in rate using old 2011 population estimate of 50 586 757 |
Change in rate using new 2011 population estimate of 51 579 548 |
CONTACT CRIME (CRIMES AGAINST THE PERSON) |
||||||
Murder |
15 609 |
16 259 |
650 |
4.2% |
0.80% |
2.78% |
Total Sexual Crimes |
64 514 |
66 387 |
1 873 |
2.9% |
-0.42% |
1.53% |
Attempted murder |
14 859 |
16 363 |
1 504 |
10.1% |
6.57% |
8.66% |
Assault with the intent to inflict grievous bodily harm |
192 651 |
185 893 |
-6 758 |
-3.5% |
-6.62% |
-4.79% |
Common assault |
181 670 |
172 909 |
-8 761 |
-4.8% |
-7.90% |
-6.09% |
Common robbery |
52 980 |
53 540 |
560 |
1.1% |
-2.21% |
-0.29% |
Robbery with aggravating circumstances |
101 203 |
105 888 |
4 685 |
4.6% |
1.25% |
3.24% |
CONTACT-RELATED CRIMES |
||||||
Arson |
6 418 |
6 064 |
-354 |
-5.5% |
-8.57% |
-6.77% |
Malicious damage to property |
122 221 |
121 113 |
-1 108 |
-0.9% |
-4.11% |
-2.22% |
PROPERTY-RELATED CRIMES |
||||||
Burglary at non-residential premises |
70 041 |
73 630 |
3 589 |
5.1% |
1.73% |
3.73% |
Burglary at residential premises |
245 531 |
262 113 |
16 582 |
6.8% |
3.31% |
5.33% |
Theft of motor vehicle and motorcycle |
59 097 |
58 370 |
-727 |
-1.2% |
-4.42% |
-2.54% |
Theft out of or from motor vehicle |
130 475 |
139 658 |
9 183 |
7.0% |
3.58% |
5.61% |
Stock-theft |
30 949 |
29 894 |
-1 055 |
-3.4% |
-6.53% |
-4.69% |
CRIMES HEAVILY DEPENDENT ON POLICE ACTION FOR DETECTION |
||||||
Illegal possession of firearms and ammunition |
14 461 |
14 872 |
411 |
2.8% |
-0.48% |
1.47% |
Drug-related crime |
176 307 |
206 825 |
30 518 |
17.3% |
13.52% |
15.75% |
Driving under the influence of alcohol or drugs |
69 441 |
71 065 |
1 624 |
2.3% |
-0.97% |
0.98% |
OTHER SERIOUS CRIMES |
||||||
All theft not mentioned elsewhere |
377 432 |
362 816 |
-14 616 |
-3.9% |
-6.98% |
-5.15% |
Commercial crime |
88 050 |
91 569 |
3 519 |
4.0% |
0.64% |
2.61% |
Shoplifting |
71 848 |
71 309 |
-539 |
-0.8% |
-3.96% |
-2.07% |
SUBCATEGORIES FORMING PART OF AGGRAVATED ROBBERY ABOVE |
||||||
Carjacking |
9 475 |
9 990 |
515 |
5.4% |
2.03% |
4.03% |
Truck hijacking |
821 |
943 |
122 |
14.9% |
11.15% |
13.33% |
Robbery at residential premises |
16 766 |
17 950 |
1 184 |
7.1% |
3.60% |
5.64% |
Robbery at non-residential premises |
15 951 |
16 377 |
426 |
2.7% |
-0.65% |
1.30% |
OTHER CRIME CATEGORIES |
||||||
Culpable homicide |
11 788 |
11 395 |
-393 |
-3.3% |
-6.46% |
-4.62% |
Public violence |
1 152 |
1 783 |
631 |
54.8% |
49.78% |
52.72% |
Crimen injuria |
31 858 |
29 040 |
-2 818 |
-8.8% |
-11.79% |
-10.06% |
Neglect and ill-treatment of children |
2 949 |
2 758 |
-191 |
-6.5% |
-9.50% |
-7.72% |
Kidnapping |
3 874 |
4 333 |
459 |
11.8% |
8.24% |
10.36% |
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