Problems with the BCS:
- It doesn't cover under 16s, who are proportionately more likely to be the victims of crime than adults.
- It doesn't cover crimes that aren't specifically directed at an individual, so for example if a school suffers an arson attack or some shops suffer theft then it doesn't show up on the BCS.
- It doesn't cover crimes against those who aren't permanent residents of the UK, such as tourists or migrant workers.
- It doesn't cover murder.
- The sample is not truly random as there are a large number of people who decline to take part and they are concentrated in high crime neighbourhoods.
- People's recall of what has happened to them over the course of a year is pretty poor.
- It doesn't cover repeat offences against the same victim, or to be precise it caps the number of offences it records.
Update: Stephen Pollard writes in the Daily Mail about the BCS's shortcomings.