How to Make a 29% Increase Look Bigger: Numerosity Effects in Option Comparisons

Consumers prefer quantitative to qualitative information, yet the same quantitative information can appear as different numbers (e.g., 7-year warranty = 84-month warranty). The current paper demonstrates that consumers focus more on the number of units (7 versus 84) than on the type of units (year versus month), which implies a unit effect. The same attribute difference expressed as a higher number of units induces a perception of being larger (Study 1). When consumers receive the same information on different scales, the unit effect disappears (Study 2). Because differences in quality for the various options appear inflated due to the use of a scale with more units, consumers may switch away from a lower quality option when the quality ratings employ many units (Study 3). Finally, the unit effect implies that consumers are more sensitive to proportional differences and ratios of attribute levels when the attribute expression relies on many units rather than a few units (Study 4).