The focus of this paper is assessment of the effectiveness of Traveling Engineering Activity Kits (TEAK) in engaging pre-college students in engineering-related activities. This includes a discussion of the challenges in assessing such a brief interaction with groups of middle school students with widely varying backgrounds as well as a discussion of how past assessment has led to modifications in TEAK activities. Program assessment has evolved from pre- and post-visit quizzes on technical content and interest in engineering to instructor observation of student engagement during TEAK visits relative to engagement during a typical class period. Initial results from pre- and post-visit quizzes showed that the vast majority of students self-reported an increased interest in engineering but that the percentage of students showing an increased understanding of engineering topics was highly dependent on the background of the students. Students who did well on the pre-visit quizzes would show less improvement after a TEAK visit, because their initial level of knowledge was higher. In the present model of rating levels of student engagement during TEAK visits, results seem much more promising, with teachers indicating that, during TEAK activities, their students are more engaged and ask more and better questions than during a typical class.