If you're referring to HBS situation researches, professors frequently hire grad students as analysis assistants to write all of them.
For instance, here's a vintage job publishing from someplace regarding Harvard Law class web site for an HBS research associate job:
Analysis Assistant (temp place), Harvard Company School
Research Assistant necessary to assist HBS professors user with an incident research focused on the protection of intellectual residential property and pharmaceutical patents in Asia. The work requires document analysis, drafting an instance narrative, and constructing situation exhibits. Just the right individual could have excellent writing skills, an ability to meet due dates, to conduct in-depth fact-checking and information searches, including a stronger fascination with China and/or company and law. The position is short-term, calling for 8-15 hours each week, for a total of 90-100 hours, and can begin straight away. Depending on spending plan, the contract is renewed toward extra tasks. Oriental skills aren't required, but a bonus.