INTRODUCTION The accreditation body for engineering, ABET, in the document, Criteria for Accrediting Programs in Engineering (EAC, 2004), provides a set of program criteria that emphasizes the outcomes of education. R~comm~nd~d uutcum~s include that engjneering ~udent~ mu~ demon~rate that th~y hav~ an ability tu: (a) apply knowledge of mathematics, science, and engineering, (b) design a system, component, or process to meet desired needs, (c) function on multidisciplinary teams, (d) communicate effectively, and (e) use the technique~ ski11~ and modern engineering tools necessaiY for engineering pradice. These outcomes emphasize not only important knowledge and skills necessary for design, but also place a major emphasis on the social aspects of engineering work-the ability to work in teams and to communicate effectively. Currently, considerable research exists which indicates that student learning of engineering content is more meaningful if it occurs in settings involving group work (Prince, 2004; Smith, Sheppard, Johnson, & Johnson, 2005). Smith et at (2005) provide a review of cooperative (Le., small group) and problem-based learning that are consistent with the criteria set out by ABET. They describe three ttL1ivities fundHmental to prodlll-1ive gruup wurk that are alsu associated with highquality ~udent thinking and rneaningfullearning. These art:: (1) wurking together with other students, (2) talking through material and, (3) solving problems tOgrlher. Although this research confirrns that. group work is an effed.ive means for :-.1udents to leHfII engilleerillg cmifent ill grllerHI) few. .. . 1I1dies exi,,1 thai exmnine the impad of group work on one particular fundamental skill of engjneering-leaming to design. The primary contribution of this chapter, therefore, is to describe the ways in which engineering students' working in groups did or did not engage in the process of design as they developed mathematical models in a prublem-solving session lasting less than 90 minutes. A second purpose of this chapter is to illustrate how to use observational methodology as a research approach to inve~igate ~1udent~ engagement and leHfliing during smHll group prohlem solving and to raise questions for further research.