Steve Smith writes .. Yesterday I began looking at the importance of customer service. Data shows that some retailers need to work harder than others to earn people’s recommendations.

People who do most of their shopping at M&S Food, Aldi or Lidl are most likely to tell their friends if these retailers impress them, whilst Waitrose, Tesco and John Lewis shoppers are least likely.

Today, I’m looking at the other side of the coin. Which shoppers are most likely to tell their friends if the retailers at which they shop let them down? It turns out that M&S customers are not only most likely to tell their friends if M&S pleases them, they are also most likely to tell their friends if it disappoints them. Although Waitrose customers are among the least likely to recommend the supermarket following good experiences, they are among the most likely to tell their friends if they feel let down. Evidently, both retailers need to be careful in their dealings with customers.

I looked at John Lewis yesterday because people often cite the department store as an exemplar for good customer service. Although its customers are least likely to recommend the brand if they are impressed with it, they are also among the least likely to pass on any criticisms. Although questions about recommendation and criticisms are about brands in general, John Lewis customers may be reluctant to censure the department store to friends because of its apparent overall good customer service. However, this is likely to change if for some reason people begin to feel let down by it.