This article originally appeared on CMO.com.

Forget Mad Men. Today’s marketers are more likely to be math men and women.

They plumb the depths of big data with advanced analytical tools. They buy and use dazzling new software. Some spend more on technology in a given year than their companies’ IT departments. They are hot on the trail of marketing’s Holy Grail, the ability to measure return on investment on every campaign.

These are laudable pursuits, up to a point. The trouble comes when marketers mistake the algorithm for the person. Great marketers tell compelling stories about their brands through memorable messages and indelible images. At its best, this kind of marketing pops and dazzles, like magic. Marketing that ignores the magic and relies on math and science alone will be marketing that doesn’t work.

Sometimes the magic is simple. The grocery chain Wegmans, for instance, created a mobile app that lets consumers select a recipe at home. The app then adds the ingredients to the customer’s shopping list and provides a route through the store layout.

Other companies have developed more complex digital-physical magic. The Chinese cosmetics company Jahwa provides reps on the sales floor with mobile devices that can tap into an integrated database. When the rep puts in the name of the customer she’s serving, the device provides data and recommendations tailored specifically to that customer—similar to the recommendation engine that consumers now experience on many digital sites.

Read the full article at CMO.com.

Laura Beaudin is a partner in Bain & Company’s Customer Strategy & Marketing practice. Mark Brinda is a partner in Bain’s Technology, Media & Telecommunications practice.