I started teaching my fitting class this week, and it's always fun to start with a new group of students that are excited about the prospect of sewing well fitting clothing.
One of the first things we discuss is the role of a fit model, and how it relates to the fit of clothing (or a pattern). In ready-to-wear, a company refines the fit of a new design around a particular body type from their customer base they consider average. Fit models can come from an agency, or they advertise to find a person to fit that criteria. For some companies, their fit model is sometimes considered highly classified information. Even the most exquisitely made outfit would look awful if it didn't fit, so we the public buy clothes mostly based on the fit, right? They are after the kind of fit model that will encourage sales, and as long as they stick with the same fit model, it's assumed that you will buy again. Fit is a pretty important element.
For sewing patterns, it's only slightly different. Though you can alter the fit or look however you like, I still have to start with a good fit for someone. So, I've been looking for a fit model. Again. It's harder to do than you might imagine. So who is really 'average' may I ask? Is there really such a thing? Three people with the same measurements can be very differently proportioned. Narrow back, wide in the hips, flat rear, broad shoulders, high bust, short waist, thin neck. There are any number of combination's.
The whole ordeal only proves my conviction that the best answer to the fit question is to get people sewing for themselves.