That was just one piece of advice from Robin Klein, president of Fashion Retail Group, at a RECon education session titled "How to Plug In an Outlet: Bringing Factory Stores to Your Property." 

Ultimately, it is about the shopping, Klein observed, and about the specific type of shopping that people are doing. "If our client loses sight of the value discount, it could kill the business," she said. "They need to know they're getting value. Otherwise, we're just like all the other shopping centers. It's hard to call it an outlet center if it's not mostly outlet stores."

Ninety-one percent of all outlet shoppers are looking for a deal, according to Klein. Forty-nine percent of shoppers never, or seldom, buy at full price, she said, and 70 percent of outlet shoppers say outlet centers deliver value.

Newer, successful outlet centers often offer a mix of retailers, including some that may carry full-price goods. "The H&M in your outlet carries the same products that are in the mall," said Klein by way of example. "So you have to think about that if you bring them in."

Increasingly, outlets are getting built closer to population centers, Klein said. "There was a time when there were no outlet centers where the shoppers actually lived, so you shopped them when you were on vacation," she said. "I would not open an outlet center today an hour away from the centers. Shoppers have more choices now, so they might not drive 45 minutes to your center."

Food is becoming more important at outlet centers, Klein said, as developers are finding that shoppers will stay longer if they can enjoy a meal while they are at the shopping center.

The more upscale outlet centers, such as Woodbury Common Premium Outlets, in Central Valley, N.Y.,  offer concierge services such as personal shoppers, plus digital apps and ample seating. But the main focus remains on shopping.

"Go to a regular mall, and a lot of people aren't shopping," Klein said. "At outlets, everyone is carrying bags — they're shopping."