When Rosa Chun dec-ided to test the claim that happy staff make happy customers, she made two discoveries: first, many managers believed it so implicitly that they saw no reason to research it. Second, there is no empirical evidence for such a claim.

Ms Chun is a professor of business ethics and corporate social responsibility at Manchester Business School. For her study, she interviewed 10,000 people (half were customer-facing staff, half were customers) at 13 UK retail organisations in financial services, food retailing, telecommunications and insurance. She asked: how satisfied they were, whether they would recommend a friend to work for the company or buy its products, and so on.