Numbers in the news

When people ask me about statistics they hear on the news, I suggest two questions they ought to bear in mind, and as a result of which they should employ appropriate scepticism. Those questions are:

1. What does that mean?
2. How do they know that?

Let me demonstrate. You hear there has been a 100% increase in a particularly nasty crime over the previous year. That's horrendous. The world is unsafe. We'd better legislate. But hang on. What does that mean? 100% of what? It turns out the previous year there was one instance. This year there were two instances. Stand down the national guard.

Another example to deploy question 2. I heard recently on the news that exports were up by so many percent over the previous year. How do they know that? I have several activities that count as exports. For instance, one of my main publishers is St Martin's Press in New York. As a result of selling them my books, money flows into the UK. This is an export, even if a physical object doesn't get popped in the post. But will that show up in their statistics? I can't see how. There must be many thousands of small businesses, exporting physical goods for internet sales, for example, where again I can't see how those sales will get into those export figures. The fact is, though they don't admit it, that this must be a guess - and not a very good one.