BOSTON — Credit unions whose credit cards already carry rewards programs would better differentiate from their competition by adding additional service to their cards than adding rewards programs, according to recent research from the Aite Group.

The financial service research firm's most recent report "Credit Card Rewards: Why Issuers Should Compete On Service" said that the proliferation of different rewards programs has blunted the effect impact of simply adding more rewards to cards that already have them.

"Because so many rewards cardholders belong to other rewards programs, differentiating on product–the reward program itself–is difficult," the report said. "But few (if any) rewards-providing firms help these consumers to manage the programs they belong to. As issuers look to one-up each other with ever-expanding rewards, we believe that issuers can differentiate themselves by creating a rewards hub that enables cardholders to aggregate and integrate programs."