Yes, to an extent. Vanity sizing is marking clothes down in size numerically -  so a woman who ought to be in a size 12 can believe she's a size eight in x shop, and thus will buy more from there. Clothing sizes have got larger over time, even with the edition of smaller numerical sizes - so a modern US women's 0-2, would equate to an 8 in the 1950s, a 6 in the 1970s. Unfortunately, this means that sizes such as the XS and the S have also grown, making them the smallest size available and still too large for some shitladies. Hope I explained this fucked up phenomenon moderately well!