A bit more detail and links here.
Comments have been closed for this article.
Tim Harford is an author, columnist for the Financial Times and presenter of Radio 4's "More or Less".
Learn More ›
Enter your email address to receive notifications of new articles by email (you can unsubscribe at any time).
Join 156,823 other subscribers
Copyright © 1999-2017 Tim Harford. All rights reserved.
Articles Archive • Photos by Fran Monks