Last week I had this post on the Uniform Crime Reports, and a commenter noted that skepticism was in order due to underreporting by some police departments. Across the pond there appears to be a major kerfuffle on this point. David Barrett reports in the Telegraph:
Almost a million crimes a year are disappearing from official figures as chief constables attempt to meet targets, a study by the police watchdog has disclosed.
Its report exposed "indefensible" failures by forces to record crime accurately, and said that in some areas up to a third of crimes are being struck out of official records.
Her Majesty's Inspectorate of Constabulary said violent crimes and sex attacks were particularly vulnerable to being deleted under "inexcusably poor" systems.
Although the report stopped short of accusing police of widespread "fiddling" it said there was an "undercurrent of pressure not to record a crime across some forces" and "wrongful pressure" by managers.
It means violent criminals and even rapists are not investigated, potentially allowing offenders to strike again.
From JCC
I made the comment on the OP, mentioned above, about the unreliability of UCR reports, due to both deliberate falsification and clerical errors.
I should also mention that there is gross - significant - error in reporting of crime clearance rates, which is claimed number and rate of crimes solved by law enforcement. These are falsified on an industrial strength level, for everything from petty theft to murder, showing crimes solved are higher than reality by whole numbers. Claims of crimes solved are never tied to actual prosecutions, so of course, room for fradulent claims is Gruber-sized. Again, from personal experience.
Is there any data in this universe we can/should trust?
Put better: What are the least untrustworthy data on crime?
by JCC
I am certain that somewhere, some police agencies are rigorous in reporting crime and clearance. Unfortunately, there exists no (real) independent audit function, and the potential benefits in under-reporting crime/over-reporting efficiency in terms of agency management longevity and (elected) political stability outweigh any antediluvian predisposition toward honesty. There really only is the single standard of the FBI Uniform Crime Reports. As agencies and department heads realize the scams go unchallenged, the propensity spreads. So, how to tell the lies from the more accurate?
So, in answer to your question...I haven't a clue.
For national totals, the National Crime Victimization Survey provides a valuable cross-check. However, the sample size of that survey is insufficient to go down to the state and local levels.
Differences in the two measures are discussed in this post.