Michael Allen's Leaving ADDIE for SAM, reviewed at http://www.learningsolutionsmag.com/articles/1012/, looks worth a read. The preface is available as a free download from Allen Interactions (yes, they will want your contact info).
The point is that the time-honored ADDIE model (Analyze, Design, Develop, Implement, Evaluate) used in instructional design is not exactly, shall we say, nimble. It's slow, cumbersome, and does not always lead to a good, finished product. It's too easy to get sucked into endless trips back to the drawing board.
He says "The foundation of any traditional process is an accurate analysis. You can’t move forward until the analysis is complete and flawless – the problem with that is no analysis can ever be complete and certainly not flawless. So, training departments get stuck in the Analysis Paralysis – and the schedule slips and keeps slipping."
Allen suggests SAM --the Successive Approximation Model -- as a replacement. Sketch a broad picture of the product you're designing, then go into depth, then iterate/refine -- but only a few times. I've worked on too many project that are in revision as soon as they launch -- I think he's onto something here.
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