Usability problem identification using both low- and high-fidelity prototypes

In two experiments, each using a different product (either a CD-ROM based eleclxonic book or an interactive voice response system), we compared the usability problems uncovered using low-and high-fidelity prototypes.One group of subjects performed a series of tasks using a paperbased low-fidelity prototype, while another performed the same tasks using either a high-fidelity prototype or the actual product.In both experiments, substantially the same sets of usability problems were found in the low-and highfidelity conditions.Moreover, there was a significant correlation between the proportion of subjects detecting particular problems in the low-and high-fidelity groups.In other words, individual problems were detected by a similar proportion of subjects in both the low-and high-fidelity conditions.We conclude that the use of low-fidelity prototypes can be effective throughout the product development cycle, not just during the initial stages of design.