The sandwich method is describes the American approach to giving negative feedback. Its goal is to communicate criticism in a way which will avoid demotivating the other person. Like a sandwich with a slice a bread on both the top and the bottom, praise is given at the beginning and the end of the feedback talk. In the middle is the substance of the conversation, the points of criticism. Open with praise. Communicate criticism. Close with praise.
Is there anything new about this? Research on the American approach to communicating criticism over the last fifty to one hundred years would probably show that it is not. American ears know to listen carefully after the positive has been said. They listen for the nuances, the terms used, especially the euphemisms. This makes it all the more complex and difficult to understand for non-Americans, regardless of strong their command of the English language.
„You did a fine job.“