Simpson was a traditionalist coach, tending to emphasise the fundamentals of batting, bowling and fielding. He has criticised the 21st century style of coaching, which has increasingly used computer technology, biomechanics and science to recommend playing techniques, stating that it had verged into "computers for computers' sake". He also coached the Netherlands national cricket team, overseeing a successful ICC Trophy campaign which saw them qualify for the 2007 Cricket World Cup. Simpson called for the Netherlands to be incorporated into the English domestic league so that they could gain more experience.