The reward gap in hierarchical loyalty programmes: how to enhance bottom-tier customers' loyalty without alienating top-tier customers

Reward gap is the difference in the number and nature of rewards allocated to specific customer groups (or tiers) in a hierarchical loyalty programme. Building on the social comparison, equity and attribution theories, and two experiments conducted in a retailing context, we investigate the effect of reward gap size and visibility on both bottom-tier (BT) and top-tier (TT) customers. Findings from Study 1 show that a large reward gap reduces loyalty to the programme in BT customers, while it enhances it in TT customers. These effects are mediated by perceived fairness and perceived control. Findings from Study 2 show that a non-visible large reward gap increases loyalty to the programme in BT customers without affecting it in TT customers. This effect is mediated only by perceived fairness. Altogether, the findings highlight the mechanisms that explain the effect of the reward gap on BT and TT customers' loyalty to the programme.