By Wan-Ju Iris Franz, PhD—“Size inflation,” also known as “vanity sizing,” is a phenomenon where the measurements of the same label size have been growing over time (The Economist). For instance, size 14 in Sear’s 1937 catalogue has similar measurements as a size 8 in 1967, which is a size 0 in 2011.
In my 2017 paper “Economics of vanity sizing” published at the “Journal of Economic Behavior and Organization” (an A* scholarly journal), I examine size charts from 54 American apparel brands. Evidence demonstrates that sizes are systematically inflated for women’s apparel brands with moderately higher prices. However, for women’s apparel, very expensive designer brands measure significantly smaller than moderately higher priced brands. Furthermore, measurements of apparel brands that target younger consumers (such as Abercrombie & Fitch and Express) are significantly smaller than their counterparts that target older consumers (such as Talbots). Finally, evidence suggests no “vanity sizing” in men’s and children’s apparel.
Although only the owner of the garment can see its label size, some people do care about what the label says. In a survey, I find that women wearing label size “large” or above particularly care about what the label says. Specifically, if there are two identical shirts—that is, the two shirts have the same color, shape, size, and price, but one labeled as “L” while the other labeled as “XL,” then this group of women, who are currently wearing large and above, would pick the shirt labeled with a smaller label size. In contrast, men, as well as women wearing size “medium” and below, in general do not care about what their clothing label says.
Men and Children
To make female customers feel better about their figure and self-image, as well as the clothes they purchase, apparel brands deliberately inflate the measurements of each label size. As size XL is relabeled as L, then size L must be relabeled as M, and M as S, and so on — like a domino effect. However, because men do not care about what their label size says, and small children do not know or care what label sizes they are wearing, there exists no vanity sizing for men’s or children’s apparel.
The Hidden Dangers
While vanity sizing might make female consumers feel better, there could be potential public health issue for the practice of vanity sizing. If the same label size is growing with the consumer’s waist circumference, then the consumer might be less aware of her own weight gain. As a result, she will less likely take actions to stay fit. As research shows that health care cost is positively associated with obesity, the practice of vanity sizing could result in negative externality in the health care system.
Next time when you go shopping, do not take it personally what the label size says about you; specifically, whether the size label indicates small, medium, or large. The label says nothing about you or your size. Rather, the label says something about the retailer, which is simply trying to maximize its profit.
Wan-Ju Iris Franz, Ph.D.
Visiting Assistant Professor of Economics, Cameron School of Business
 Daily chart: Size inflation. (2012, April). The Economist; retrieved from: https://www.economist.com/blogs/graphicdetail/2012/04/daily-chart-1
 Clifford, S. (2011, April). One size fits nobody: Seeking a steady 4 or 10. The New York Times, retrieved from: https://www.nytimes.com/2011/04/25/business/25sizing.html