Recently I heard someone make the statement that you need in describing a system using models, you need to find the proper balance between precise models and flexible models.

In this context, precise models would be models that are correct, are as complete as possiblem flexible models would be models that are less correct but are capable of conveying information to stakeholders (mostly business people).

I would dare to state that above is not correct.

The chapter on viewpoints in the ArchiMate specification, makes a distinction between three types of viewpoints (models):

Deciding Viewpoint. Models in this category are meant for people who need to make decision, decide on trade-offs. They typicall compare several alternatives based on a list of criteria.

Informing Viewpoint. Models in this category are meant for people who need to get or give information on the system. They must be adapted to whatever area of interest and level of interest the audience has.

Designing Viewpoint. Models in this category are meant for people who have to further design and build the system. These people need completeness and precision.

So back to our inital question: do we need to find a balance between precision and flexibility in models describing a system? I say: no. You need precise models and you need flexible models. It depends on what they are used for (deciding, informing, designing) and who they are intended for.

If you insist on making only one set of models, for all stakeholders and for all purposes, there is no end to the amount of damage can you do. If you find yourself deciding on ‘the right balance’ in a model, take a step back and see if you are not trying to model the system using a one-size-fits-all model.