When is this a problem?
This is a problem when you have unnecessary dimensions—meaning that the logic or data in the module does not apply to the dimension.
Why is this a problem?
Unnecessary dimensions in a module could cause poor performance from a formula having to perform unnecessary calculations and increasing the size of the model. It can also hinder the end-user experience by causing them to have to use unnecessary context selectors, which can lead to confusion or cause extra difficulty trying to get to their desired view.
How to correct:
Remove the unnecessary dimensions. This could cause your formulas to become invalid and thus cause an error. If this is the case, set your format to No Data, remove the dimension, update your formula, and then reset the format. You may have to modify downstream line items if they use the current line item as a mapping or variable.
Model Size and Dimensionality
The Truth About Sparsity: Part 1
Questions on this topic? See What dimensions are used in the module? Are they all necessary? in our Model Optimization Checklist forum.