Must read Goldacre on data analysis.
Funnel plots are not something I knew much about, but of course it makes sense that you would expect more variation in smaller sample sizes. All data comparing cities and countries should be put through this kind of wringer.
DIY statistical analysis: experience the thrill of touching real data
Ben Goldacre: The story of one man's efforts to re-analyse the stats behind a BBC report on bowel cancer is a heartwarmingly nerdy one