Methods are individual strategies or tools that can be used in many different types of evaluation. Classic example is surveys and interviews. they are both data collection methods than can be used in almost any kind of evaluation. But there are also different sampling methods, different analysis methods that one can use.

Approaches combine multiple methods within in a very intentional framework or logic. E.g. RCTs can involve surveys and all kinds of other data collection methods. It can involve random sampling methods and it can also involve counter-factual analysis methods. But it packages these in a particular way and together they make up an approach.

As for design, we don’t define this in the Rainbow Framework. But I would say that your evaluation design is the result of the all the choices you make about methods and approaches in response to the context and purpose. Every evaluation has a different design and very rarely is a design copied exactly (unless it’s as part of a replication study).

So to answer your question, this is how I would define these items…

Case Study – approach
Pretest-Posttest Control Group – method
Ethnography – approach
Investigatory – investigatory what? this is more of a purpose
Naturalistic – naturalistic what? ditto
Random Control Trials (RCT) – approach
Quasi-Experimental – a family of methods (e.g. difference in difference, regression discontinuity, propensity score matching…)
Qualitative – a type of data, distinguished from quantitative
Focus Group – method
Needs Assessment – method

You have a lot of comment spam (like email spam) definitely don’t respond or accept. I don’t know who does your Wordrpess programming but I would suggest adding a plugin (either askimet or spam free wordpress). This should vastly limit the spam you receive.

From my experience, sparking conversation and pulling in traffic require two things, (1) great content styled for the web and (2) spreading the word about your great content.

Evaluating web content also has a lot to do with the structure of that content. Some structures are much easier to evaluate than others.

I’d suggest trying something new and direct. #5 in your list gives me an idea for a collaboration, any interest? The result would be a piece of content that is easier to evaluate. I have a few things coming up, but if you’re interested I’ll get in touch via email within the next couple of weeks.