"To be certain your fashion will fit when it is completed, be sure your pattern measurements are similar to those of your body. By comparing your measurements plus ease to the actual measurements of the pattern pieces, alterations needed for good fit can be made before your pattern is cut out.
The amount of ease in a pattern will vary from fashion to fashion and from one brand of pattern to another. Because of this, your usual size 12 pattern may not always fit you. Use this checking procedure to help insure proper fit in your finished fashion."
- College of Agriculture and Home Economics New Mexico State University