Consumers consider the value of a cellphone differently depending on whether its warranty is expressed in years or days, European researchers say. What may seem an arbitrary choice of the units used to describe product features can have profound consequences for consumer product evaluations, researchers at Ghent University in Belgium report in the Journal of Consumer Research. In the study, they found switching from standard to alternative units can negatively impact how consumers evaluate products. For example, they said, a product with a warranty of 731 days was rated more negatively than a product with a warranty of 2 years, even though these warranties are equivalent. However, this negative effect mostly occurred when a product was shown in isolation, the researchers said. While a warranty of 731 days may appear strange when consumers see it alone in an advertisement, if they were to compare this product to others listed with warranties of 550 or 365 days their focus would shift to the numerical difference between warranties. \"Consumers prefer to receive product information in small numbers, but also want this information to provide sufficient distinction between products,\" study authors Christophe Lembregts and Mario Pandelaere wrote. \"Default units strike an optimal balance between both needs by providing specific product information in rather small but accurate numbers.\"