Reader question — When not to build a model

Reader question on When not to build a model, and the answer belongs somewhere more findable than an email.

The most valuable modelling skill is recognising the problems that do not need one, which is a large majority of the problems people bring you.

The question was, roughly, "when does this stop applying?" — which is the right question and the one lessons routinely fail to answer. Every technique has a range of validity, and stating it is what separates a lesson from a recipe.

It sits in the Modelling, honestly module. The exercise is a thinking one rather than a query one — some of this material is about deciding what to compute, and that does not need a keyboard.

Ordering matters here more than in most courses. It follows Features, and explaining what the model did and leads into Choosing the form before the colours, and reading it out of sequence mostly works but costs you the setup.

Free means free, and it also means we can rewrite it whenever it is wrong. No edition, no errata PDF, nothing to repurchase. The whole course is 36 lessons and the fixes land the day we find them.