Fashion can be a fast-paced, fickle industry. What’s trending one season is out the next. And as production times decrease and the avenues fashion retailers have to identify emerging trends increase, some retailers can react to market movement in just a matter of weeks. eMarketer's Lauren Fisher spoke with Andreas Reiffen, founder and CEO of retail performance advertising company Crealytics, about how fast-fashion retailers are using data from channels like search and social to be more efficient beyond the marketing department. Reiffen was interviewed as part of eMarketer’s August report, "Using Marketing Data for Merchandising: Optimizing Inventory Levels and Launching New Products."

That information is then relayed to a buying or product system to get a sense of how much a brand will need to either purchase or produce based on the user behavior you see.