A smaller number on the label helps the sale, so labels drift downward

The argument

The vanity-sizing explanation starts from the fact that the number on a label is doing two jobs. It describes a garment, and it tells the wearer something about themselves. Proponents of this explanation argue that the second job is commercially the more important one: a shopper who finds they take a smaller size in one shop than in another leaves with a better impression of the shop, and the garment that flatters is the garment that gets bought. Since nothing fixes what a size number must mean, a retailer can supply that flattery directly, by attaching a smaller number to the same measurements. The mechanism, on this account, is competitive rather than conspiratorial. Once one retailer's sizes run generous, the brands a shopper compares it with appear to run small, and the pressure is on them to follow. The result is a ratchet: numbers can be moved down easily and cannot be moved back without telling customers they have gone up a size. Proponents argue that this is why the inconsistency has a direction, and why it has proved so hard to reverse. They also argue that the explanation accounts for where the effect is strongest. It is most visible in clothing whose size number is read as a statement about the body, and weakest where the measurement is given directly, as in garments labelled by stated dimensions rather than by an abstract size. On this reading erratic sizing can be fixed, but not by asking brands to be tidier: it requires labels that state measurements, because a number that describes the wearer will always be worth more to the seller than a number that describes the cloth.

Premises

Counter-arguments

Critics reply that the account attributes to intention what drift explains adequately on its own. Fit models are chosen from the customers a brand actually serves, and as that population changes the middle of the range moves with it, producing the same one-way shift with no decision to flatter anyone. They add that the explanation struggles with variation running the other way: ranges aimed at younger buyers are routinely cut smaller than the same brand's main line, which a flattery ratchet would not predict. On that view vanity sizing names a real commercial temptation but is being asked to carry the whole explanation, when the simpler account is a product specified loosely against a reference body that keeps moving.

Rejecting the premises

[Rejecting P1] That a label carries a self-image is a claim about meaning rather than about buying, and shoppers who return garments which do not fit are responding to the measurement and not to the number. [Rejecting P2] A retailer that labels generously loses the customers who rely on its size chart, so competitive pressure runs in both directions rather than only downward. [Rejecting P3] The ratchet argument assumes sizes are never recut, whereas brands revise their grading regularly and some ranges are deliberately cut small. [Rejecting C] At most it follows that flattery is one pressure acting on sizing, not that it is why sizes differ.