A useful distinction
A chest width measured with a garment laid flat differs from a circumference or a body measurement. Without a method, the same number can be interpreted in several ways. Consistency matters more than adding an unexplained precise-looking figure.
Put it into practice
Describe how the garment was positioned and which points were measured. Include the unit and keep the item reference visible. Avoid stretching or altering the garment to produce a preferred number, and distinguish a measured dimension from an estimate or a manufacturer’s size chart.