ABSTRACT
OBJECTIVE: To determine whose naive judgments of consumer product usability are more accurate--those of younger or older adults. Accuracy is here defined as judgments compatible with results from performance-based usability tests. BACKGROUND: Older adults may be better able to predict usability problems than younger adults, making them particularly good participants in studies contributing to the user-centered design of products. This advantage, if present, may stem from older adults' motivation for more usable products or from their experience adapting their own environments to meet their changing physical, cognitive, and sensory needs. METHOD: Sixty older participants (ages 65-75 years) and 60 younger ones (ages 18-22 years) evaluated illustrations of consumer products on specific criteria (e.g., readability, learnability, or error rates). They either rated a single design for each product or ranked six alternative designs. They also explained their choices, indicated which features were most critical for usability, and selected usability-enhancing modifications. RESULTS: Although there was no reliable age difference in the amount of usability information provided in the open-ended explanations, older adults were more accurate at ranking alternative designs, selecting the most usability-critical features, and selecting usability-enhancing modifications (all ps < .05). CONCLUSION: The usability judgments of older adults are more accurate than those of younger adults when these judgments are solicited in a fixed-alternative, but not open-ended, format. APPLICATION: Because older adults are more discerning about potential product usability problems, they may be particularly valuable as research participants in early-stage design research (prior to the availability of working prototypes).
