This project aims to further our understanding of the practice of user-centered design (UCD) by observing the argumentation strategies used by designers in faceto-face meetings in the critical periods between usability research and prototype iteration. In order to conduct such an investigation, I recorded ten meetings of graduate student designers charged with redesigning documents for the United States Postal Service. I then used discourse analysis techniques to determine how the designers used findings from research phases as evidence to support proposed design decisions in meetings concerning prototype alterations. Results show that these designers overwhelmingly do not support their design decisions with specific evidence from usability studies. This neglect of research-based evidence may indicate that these novice UCD designers may resort to designer-centric design behaviors in decision-making periods. My analysis will focus on the rhetorical reasons why designers may avoid resea...