Christian Louboutin shoes (Knowledge @ Wharton High School)

Analysts have been sounding the alarm bell about the death of retail for a few years now. A few categories are also shifting. Among them are various trends in womenswear. Right now, one major category is getting shaken up: women’s shoes.

Market research firm NPD Group found that sales of high heels dropped 17% in 2017. The women’s footwear category then saw a substitute effect: Sales of women’s sneakers jumped 37% within the same time period.

There are a few reasons at play here: One is that the office is getting more casual, and it’s more acceptable for women to wear flats to work. Another is that sneakers are also having a moment in casual wear. An overarching reason is that women are claiming what they want to wear, and not bending to society’s expectations.

We can’t yet say if this will be a trend for retailers, or the beginning of a larger shift. It may be time to find out how men respond to flats and sneakers in terms of attraction.