Emily Geesaman asked the title question on Linkedin a couple of days ago.
Two folks, Susan Maxwell Stevens and Karen Derby, APR, both observed that the answer depends on the kind of background the PR pro has. If a business undergraduate degree, then perhaps a Master’s in communications would make the most sense. If a journalism major, then perhaps an MBA. Certainly, I agree with their counsel.
That said, the more I watch communications and business evolve, the more convinced I am that the MBA is, in general, the better choice. We talk in communications about managing reputations and relationships. But the truth of the matter is this is not done through communications so much as through the actions of the organization. And those actions are driven by management policies. Organizations may be able to communicate their way out of bad behavior once or even twice, but they cannot do this consistently. The new drive towards transparency requires that organizations act in ways that are consistent with the norms of their stakeholders and the society in which they operate. This is managed at a policy level, not a communications level.
So, if you want to make a difference in the organizations for which you work, or if you even want to be able to execute communications programs that are effective (because they say things that are to stakeholders reasonable and true), you will have the greatest likelihood of doing so if you are a part of the management team of your organization. Understanding what MBAs understand will help you be a part of that team more than understanding what communicators understand.
Of course, understanding both is best.