No one likes to tell someone else they’ve done a poor job or received a bad mystery shop. It’s one of those things most managers never get used to having to do.
Which is why mystery shopping is an excellent, non-biased way to be able to start a discussion with a less than stellar employee. (It’s also a great way to acknowledge those excellent employees too!)
Starting the discussion after a mystery shop has been performed provides you with written observations from a third party. The third party being a potential or actual customer.
The report isn’t your opinion or observations of their co-workers. It is of a real interaction. A great basis for a real discussion on what went right and what did not.