For example, patterns produced in the 1990s for a size 36” / 90cm bust measurement would have a size code 14 but previously, in the 1950s, the same bust size would have had a size code 12. A VERY IMPORTANT fact to remember … especially if you happen to be using a non-current pattern and more so if it has lost some of the sizing reference details.
Another thing that has changed is the pattern primer or in other words ... the making-up instructions.
The cutting layout has only changed slightly, mainly as a result of choices regarding fabric widths. However, it is the sewing instructions that have seen the biggest change with more detail being provided as well as ease of understanding. A greater variety of construction methods is now seen, many closely following those methods used within commercial practice. Additionally, there is more use made of current sewing machine, their range of accessories and other items of varied haberdashery.
Also, the pattern pieces are now quite different to those of the past. Back in the 1950s (and earlier), tissues had no actual printed markings - just a few perforations and notches. Today, they have placement lines and arrows, seam guides, descriptions, design marks and many other notations. All there to make sewing so much easier and quicker !