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Model versus system
The model is one component. The system is everything around it.
Almost every conversation that goes wrong between a technical and a non-technical person confuses these. Choosing a better model changes a small fraction of the outcome. The workflow, the permissions, the data access, the exception handling and the evidence are the rest of it, and they are where the work is.
Why it matters
“Use a better model” almost never fixes a failed deployment.