assessment v. evaluation

Most of the library staff we interviewed for this project talked to us about community and/or customer needs.

But I’m having a bit of a quandary as I think this through: I have the “assessment” section of my work separated from the “evaluation” section of my work, and I’m wondering if that makes sense. In my mind, assessment is a separate function. You do it first to identify customer needs (or unknowns) as well as scan the environment you’re playing in. You use this to inform your design or evolution of library services as you map it to your organization’s core competencies & maybe even existing collections and services. Evaluation comes after the first pass of service delivery – it’s the first (and ongoing) look at how you’re doing against the goals you’ve set as a part of your initial planning.

In my literature review of the needs assessment function as it relates to library service places it almost always in the context of evaluation. My question: is anyone doing one and not the other? Do you think of them as separate functions? Or, are they inextricably linked?