You are right that using a look up table only moves the problem one level deeper, but in doing so, it may make it easier to control and limit the opportunity for mistakes. For instance, you may have vets joining and changing specialties often enough that some less knowledgeable user may need to have authority, but perhaps the look up table will need additions rarely enough for the DBA to handle it, or at least rarely enough that there will be fewer opportunities for typos there.

The other piece of course is that with a look up table you could make front end so the user would choose from a menu instead of typing it in at all.