A former police officer says new crime statistics may have less to do with police techniques and more to do with public reluctance to report crime.
Latest annual statistics show 6.7% fewer crimes were reported last year than in 2009.
But Kim Workman, a former police officer and the director of the Rethinking Crime and Punishment group, says last year's Crime and Safety Survey gives perspective to who reports crime.
He says 94% of assaults, and 62% of robberies and theft are not reported in the police statistics.
Mr Workman says people are frightened that if they report the crimes the police might overreact.