Teaching links

A hostile report on evidence-based policy by Jamie Whyte from IEA gives a nice example of adjustment along many margins:

Seeking to improve the diets of its pupils, a school in Northamptonshire
banished vending machines in 2006. William
Guntrip, an enterprising thirteen-year-old pupil of the school,
spotted the profit opportunity this created. He started buying
large quantities of sweets and soft drinks and resold them in the
playground, making a profit of £50 a day.  (School bans boy’s snack empire’, Metro, 4 July 2006).