I'm proofreading a document in which the author ends a lot of lists with phrases like this:
We analyzed the responses of students studying: health, sciences and technology, law and economics, and human and social sciences.
Usually when I come across lists that end with two words that need to be connected by "and", I usually just substitute "as well as" or something like that. But I'm not sure if there's a standard rule for these kinds of situations. In this particular paper, there are many examples that aren't very easy to fix this way.
What's the rule?
... if there's a standard rule
. This is English; we don't have rules, just patterns. Patterns that are frequently ignored and change rapidly.