Paths of Research
Research is all about trying to find answers, especially answers that are not immediately obvious.
There are many kinds of research available to the broadcaster, but very often the broadcaster does not make use of them to help him better understand his audience or their specific needs and questions.
Read Chapter 5 of Radio Programming Roles to help you better understand about the kinds of things the broadcaster needs to know - and possible ways of finding answers.
Read Eila's page where she explores some of the findings of Audience Research.