One of the things that seems to me to distort a lot of the discussions of evidence in philosophy of science (and related areas of epistemology) is an over-simplification of the role of evidence in science and inquiry. In particular, many accounts tend to treat evidence as
mono-functional, where the only important function evidence plays is
support. The nature of that support relation might vary from account to account (Bayesianism, falsification, inductivism, etc.), but many accounts agree that this is how evidence should be understood.
In contrast, I think we can point to a number of equally essential roles that evidence plays in inquiry. When first setting out to investigate the problem, early observational evidence can help
locate or
specify the problem. When you have an outbreak of disease, or an unexpected astronomical event, you first have to gather as much evidence about the nature of the problem as possible, before you can pose hypotheses or explanations for testing / support. Gathering evidence can also actually
suggest hypotheses. A first look at the evidence suggests that this problem might be best analyzed by Fourier analysis, or a simple retrospective study design, or spectral analysis, etc., or by hypothesizing that the disease is malaria, that the new object in our telescope is a type of quasar, etc. Gathering evidence can also help with the
elaboration of a hypothesis, specifying, clarifying, or improving it. And not only can it provide support for a hypothesis by testing or confirming its predictions, but experimental testing can be understood as a type of
testing by application. If we understand experiment as a kind of intervention on the basis of a theory or hypothesis, then it is really a type of application of the hypothesis to some situation (often a highly controlled one).
So, to sum up, a (probably partial) list of the various functions of evidence: locating the problem, suggesting a hypothesis, elaborating the hypothesis, supporting the hypothesis, and testing it by application. Probably I should say something about helping specify initial conditions, too, though I'm not sure everyone would be willing to call that "evidence."
One way that idealizing evidence as mono-functional, focusing exclusively on the support relation, might go wrong, is the tendency to worry overmuch about the independent status of evidence; i.e., if evidence is to be judged solely by its suitability for providing firm support, then all of the problems of the "empirical basis" start to rear their ugly heads. I suspect that when we have a more complex picture of the functions of evidence, we can use it to develop a multi-scale analysis of the
functional fitness of that evidence, which gives as a way of assessing the adequacy of it to stand
as evidence.