The BBC has found a story: "'Threefold variation' in UK bowel cancer rates". The average death rate across the UK from bowel cancer is 17.9 per 100,000 people, but in some places it's as low as 9, and in some places it's as high as 30. What can be causing this?
Journalists tend to find imaginary patterns in statistical noise, which we've covered many times before. But this case is particularly silly, as you will see, and it has a heartwarming, nerdy twist.
Paul Barden is a quantitative analyst. He saw the story, and decided to download the data and analyse it himself. The claims come from a press release by the charity Beating Bowel Cancer: they've built a map where you can find your local authority mortality rate and get worried, or reassured. Using a "scraping" program, Barden brought up the page for each area in turn, and downloaded the figures. By doing this, he could make a spreadsheet showing the death rate in each region, and its population. From here things gets slightly complicated, but very rewarding.
We know that there will be random variation around the average mortality rate, and also that this will be different in different regions: local authorities with larger populations will have less random variation than areas with smaller populations, because the variation from chance events gets evened out more when there are more people.
http://www.guardian.co.uk/commentisfree/2011/oct/28/bad-science-diy-data-analysis