Don’ make the conclusion that personalization is mostly science. Companies today are also turning to subjective data as a part of their personalization efforts. One such company is Stitch Fix, which offers online personal stylists for women.

Stitch Fix has a subscription-based service that sends a monthly selection of five items to each customer’s door. A combination of sophisticated algorithms and personal touches from stylists helps Stitch Fix create a monthly delivery to meet each client’s budget, taste, and lifestyle. Once each month’s “fix” arrives, customers keep what they like and send back what they don’t. There’s no obligation to keep any or all items, although there is a discount should a customer choose to keep all five items. The return process offers a way for Stitch Fix to learn what customers like and take this into account for future shipments.

Stitch Fix brings together an unusual blend of art and science to deliver one-on-one personalization at scale. When asked about its personalization efforts, Stitch Fix COO Julie Bornstein told NRF: Personalization and big data are buzzwords that everyone talks about, but it’s very hard to operationalize these concepts. At Stitch Fix, we are able to deliver a “fix” of five items that have been selected to fit each individual client’s budget, taste, and lifestyle. It is personalization at a whole different level, and it’s very exciting. In some ways, it’s the combination of big and small data that is enabling us.

The combination of big data and small data is at the heart of personalization. Many companies are great at identifying big-data trends across their customer base. Magic happens, however, when you use those trends to see little-data behaviors in one customer as an indicator and respond accordingly.