To help standardize clothing sizes, there was a U.S. National Size Survey completed in 2003 measuring 6310 women, and 3691 men.

The Problem With Sizing

“How is it that a 5'8", 150lb. woman, a 5'6," 135lb woman and a 5'9," 125lb. woman all claim to wear a size 8? This, and many other fitting anomalies are the reality today for the US clothing industry, where a comprehensive analysis of body shapes and sizes hasn't been conducted for several decades. This lack of research, in addition to the growing practice of vanity sizing – adding inches to clothing to make it appear that a woman wears a size smaller than she actually does – has created a disparity between the clothes available to the consumer and their actual body shapes and sizes.  

And that's only half the problem. Companies use sales data to get feedback on what sizes are selling and in what proportions – but sales data never captures lost sales. Not only is the consuming public being poorly served by this, but the retailer and the upstream apparel manufacturer lose out on considerable sales volume. Inevitably, people are forced to have expensive alterations done or simply wear clothes with an unsatisfactory fit.  

...The SizeUSA survey, completed in September 2003, is anthropometric research developed to gather United States sizing data with the use of its 3D measurement system, a body scanner feeding data into measurement extraction software.”  

Before Standard Sizes

According to the National Institute of Standardization and Technology (NIST) Before clothing size standardization, “each manufacturer created its own unique and sometimes arbitrary sizing system based on inaccurate body data or no body data at all. Garments of widely different dimensions were frequently labeled the same size by different manufacturers.  

In 1937, the U.S. Department of Agriculture prepared to conduct a study of women's body measurements for the purpose of creating a sizing system which the entire industry could follow.
Fashions From The 1940's  

The First Mass Measurement Campaign During 1939 and 1940, about 15,000 American women participated in a national survey conducted by the National Bureau of Home Economics of the U.S. Department of Agriculture. It was the first large-scale scientific study of women's body measurements ever recorded. A technician took 59 measurements of each volunteer, who was dressed only in underwear. Volunteers were paid a small fee for participating. (which during the Great Depression provided food money for many of them. That situation may have skewed the data toward underweight body types.)  

The results of the study were published in 1941 in USDA Miscellaneous Publication 454, Women's Measurements for Garment and Pattern Construction. The purpose of the survey was to discover key measurements of the female body – that is the important measurements from which other measurements could best be predicted – and then to propose a sizing system based on this discovery.