Police revise ‘skewed’ crime rates

Police admitted on Friday that they had released skewed crime rates on Tuesday – but said the error did not affect the number of crimes recorded.

“Based on the advice from Stats SA regarding the correct estimates to use for computation of the crime rates‚ the police hereby issue a revision of the crime rates based on the 2017 mid-year population estimates as at the end of September‚” the South African Police Service said on Friday.

“The revision of the estimates will neither affect the raw crime numbers nor the nine-year crime rate trend but will only affect the last rate in the 10-year series that is, the 2017-2018 crime rate.”

Crime rates are the number of crimes that happened per 100‚000 citizens over a given period.

The revision comes after fact-checking website Africa Check noticed an error.

Police spokesperson Colonel Athlenda Mathe said Stats SA’s 2018 mid-year population estimates had been used to calculate the 2017-18 crime rates.

This means the crime rates for the 2017-2018 statistics‚ which cover April 1 2017 to March 31 2018‚ were calculated using the population estimate of June 2018.

“By using a later and larger population estimate‚ it appeared that South Africa’s population increased from 55‚843‚011 people in 2016-2017 to 57‚725‚600 in 2017-2018 – a difference of more than 1.8 million people‚” Africa Check wrote.

Based on Stats SA’s estimates‚ the population grew by 1.6% between September 2016 and September 2017.

Crime expert Anine Kriegler said: “It has the effect of making the increases in crime rates look smaller and the decreases look larger.”