When signal swamps substance: the effects of multi-unit discount’s positive and negative cues on sales

Purpose Multi-unit discounts (MUDs, e.g. “3 for $4”) typically increase sales relative to other discounting frames. This study demonstrates the value of MUDs by showing that positive multi-unit price/quantity signals are potent enough to match and even exceed the sales produced by larger discounts on single items. However, there is reason to believe that MUDs can produce neutral effects in some cases (e.g. among consumers interested in only single-unit purchases) and even negative effects in others. In addition, the study considers whether MUDs can, in some cases, reduce purchase quantities by signaling smaller-than-otherwise-planned purchase amounts and/or lower-quality products. Design/methodology/approach The effectiveness of MUDs is tested in both the field and lab. Study 1 models purchase quantities stemming from 2,374 purchases of discounted items at a mass retailer. Purchased products ranged in type from pantry items to apparel and electronics, and ranged in price from 44¢ to $99.99. There were 1,530 single-unit discounts, 596 two-unit discounts and 248 discounts, involving three or more units. Study 2 consists of a laboratory experiment that overcomes the shortcomings of Study 1 by accounting for non-purchasers, controlling for product classes and testing whether smaller MUDs can lead to lower purchase quantities for larger-purchase-quantity products. Findings The results of both the field study and the laboratory experiment indicate that MUDs’ monetary cue (savings) and purchase-quantity cue (volume) increase purchase quantities. Generally, purchase quantities increased monotonically with the number of units offered in the discount. In fact, the quantity cue is so effective that it can increase sales enough as to substitute for larger discounts. However, in some instances, MUDs can decrease intended purchase quantities. The negative effect of MUDs is the most pronounced for larger unit deals, offering deeper discounts on perishable goods. Originality/value This research is the first to demonstrate that the power of the signals provided by MUDs may be so positive as to lead them to be more effective than discounts of substantially larger value but also so negative as to render them less effective than single-units discounts. This negative outcome poses a threat beyond those typically associated with discounts, in that rather than consumers simply discounting a discount, in which case the discount remains positive even if their impact at the margin wanes, the MUD frame may actually reduce sales.