Product Engineering
"Softer" cannot be bought or disputed. A bending rigidity 25% above target can be.
— index
100 is an exact match to the target profile
The index is a management summary and the signed deviations are the engineering content — a fabric 25% too stiff and one 25% too limp score identically on the index and need opposite corrections, so never act on the composite alone. Weights should sum to 1 for the index to sit on a sensible scale, and they are category-specific: bending dominates hand for shirting and matters far less for fleece. Human perception is also not linear in any of these properties, so equal percentage deviations are not equally noticeable, and the mapping needs anchoring against a trained panel before it means anything to a customer.
Fabric Hand & Performance Specification Matrix — free, with the formula and a worked example, at Textile School.