Thanks Rachel! I guess context is key here. When you consider bounce rates, a user could leave a page because they have found what they were looking for (or directed there), or out of frustration.
What I'm trying to determine here is the relevance of content on a page. As you point out, if you've loaded an article and users aren't getting past the first paragraph, you might assume that the content isn't relevant or interesting enough. When it comes to a page that has information on a university degree or diploma (sector I'm currently working on), it becomes more difficult to work out why a user is overlooking this content.