The 'feedback sandwich' may be giving workers a bit of indigestion, and may not be as effective as you think, according to some research reported in a recent NYTimes article. The common wisdom has been to begin and end feedback to employees with positive observations, sandwiching the negative comments in the middle.
Tim Harford, author of "Adapt: Why Success Always Starts with Failure," takes issue with this. His research finds that labeling feedback as positive or negative is not useful. When the feedback sandwich is used, people often hear only the praise. Co-author Ayelet Fishbach, a professor at the University of Chicago, notes that expert employees value direct negative feedback as a way to improve. Negative feedback should be offered in clear manner that allows for creativity to flourish.
One method to do this constructively is "plussing"—using words like "and" or "what if" instead of "but" when offering criticisms. For example, you might try saying "I really like ____, and what if ____?" Ultimately, this method can be effective in making somebody's work better, not just to making them feel better.