A critical lesson from a good business writing course should be this: Know when not to put something in writing. Writing can appear evasive to readers, who may believe that the author of a written message is intentionally avoiding face-to-face contact. The option of giving feedback verbally is often unavailable in businesses that require supervisors to write performance reviews. There goes the writer's dilemma: to write or not to write.
A practical look at the better mode for delivering feedback appears in the essay "When to Give Verbal Feedback—and When to Do It in Writing" by Sarah Gershman and Casey Mank for Harvard Business Review. The authors show the strengths of both verbal and written feedback, as well as a third communication mode: the voice memo. Gershman and Mank position their piece toward the ultimate goals of feedback: building trusting relationships and cultivating the employee's skills. For a 10-minute read, the article provides a valuable start for planning to give feedback.