Sizes in women's clothing have no objective standards at all (I do so envy men's pants, which come in 34x30 rather than Size 8 Slim Petite), but Kendall Farr opens her well-known book by suggesting that women break out the tape measure anyway. Measure yourself, and then measure anything you're thinking about trying on -- it saves time.
It helps a litte but not completely. Women may be the same size and measurements, but a completely different shape (men have this problem too, right?) What we need is technology that can 3D scan an item and virtually drape it. Then I can get myself scanned and try on the virtual draping. Only then will I fully be comfortable spending real, non-returnable money on the internet for clothes (shoes and accessories are less of a big deal for fit).
Sizes in women's clothing have no objective standards at all (I do so envy men's pants, which come in 34x30 rather than Size 8 Slim Petite), but Kendall Farr opens her well-known book by suggesting that women break out the tape measure anyway. Measure yourself, and then measure anything you're thinking about trying on -- it saves time.