Does anybody out there love the RIM?

The most remarkable aspect about the wide feedback I’ve received about the HL7 Fresh Look taskforce is the comments about the RIM.

One person – just one solitary person – put it to me forcefully that the original direction of the RIM (+ design by constraint + the XML ITS) was the right direction, and that we should stay the course, becase in the end, the doubters will be overcome by the evidence.

Just one person. It’s someone I respect greatly. And it troubles me to disagree with him, because this person is often proved right. But he’s the only one (so far) (And I’m not going to name who it is since our discussion was private).

There was a long and at times passionate thread on the RIMBAA (RIM-based application architecture) email list defending the notion of the RIM, but even there the opinion there was pretty unanimous: the RIM should be reserved to specialists, and normal interoperability specifications should use simple forms where their innate RIM-ness is hidden from the normal population.

Generally, the feedback I got from my fresh look post told me loud and clear that HL7 is not reducing complexity, and that in particular, the RIM is not helping to tame complexity.

That should come as no surprise to anyone who’s read my piece on design by constraint: it simply externalises the complexity associated with achieving consistent semantics. But nevertheless, I was surprised at how  one-sided the feedback was in this area.

Does anybody (else) out there love the RIM?


  1. Keith W. Boone says:

    Love, no. Hate, no. Sort of a love/hate relationship. Reference models are necessary, but insufficient. The RIM as reference models go isn’t bad. Combined with design by constraint, cloning and a bunch of other hdf gunge, it barely had a chance to be understood.

    The purists seem to have wrapped it’s feet in swaddle to keep everything all nice and neat — neatly handicapping it.

  2. Keith W. Boone says:

    BTW: I don’t equate RIM with HDF, design by constraint or the XML ITS. It’s the foundation of a whole stack that we call V3. I think the problems with v3 start above the foundation. Not much higher up, but not so low as to require a hard reset.

  3. Rene Spronk says:

    The title of the post is misleading, for it is not actually about the RIM, but about ‘design by constraint based on the RIM’.

    Quite a few implementers on the RIMBAA group (mentioned in the post) implement the RIM as a model for their persistence layer, without necessarily using any of the contstrained and/or interoperability features that are associated with that RIM.

    As such Grahame is merely repeating his “design by constraint” post, and the title of this post should have been “does anybody out there love design by constraint?”.

    One may like the RIM without liking design by constraint, using the RIM does NOT imply using design-by-constraint (only the other way around).

  4. Grahame says:

    #Rene. While I agree that the issue of design by constraint comes up, my scope is wider. However, yes, the title is for fishing.

  5. Lloyd McKenzie says:

    If by “love” you mean “does it permeate ever design you attempt, even those that have nothing to do with either v3 or even healthcare”, then I’d have to say “yes”. Or at least the backbone part of it.

    Not sure I love design by constraint, but I definitely *don’t* love the alternatives to it I’ve encountered. At least not from a perspective of safe interoperability

  6. […] Grahame Grieve at Health Intersections: The most remarkable aspect about the wide feedback I’ve received about the HL7 Fresh Look […]

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