This is what happens on a newspaper when crime statistics come out. The news editor asks the crime correspondent what the figures mean. Is crime up or down? Are policies working or not? Is this good news or bad news? And the crime correspondent sighs loudly, runs his hands through his hair and explains that it's not as simple as that, definitions change constantly, and that often crime stats look better because people don't bother to report crime, and the Home Office tinkers incessantly with the way crimes are reported.
The conversation generally ends with the words: 'Always remember that crime statistics can generally mean whatever you want them to.'
I know this because fifteen years ago I was working as a news editor for a national broadsheet. And judging by today's news things haven't changed much.