Build IT is a technology fluency program for middle school girls developed by SRI International and Girls Inc. of Alameda County. One of the program's goals is to encourage participants to explore and pursue careers in STEM fields. To do this, girls create technologies and meet women working in STEM fields. One of the challenges for evaluators has been measuring subtle shifts in girls' interest in STEM and related careers. We found that staff who work with the girls daily saw more interest in STEM than we picked up via surveys and interviews. For example, students loved creating video games stuck to answers like "teacher" and "pediatrician" when asked by evaluators what careers interested them. In this paper, we discuss modifications to interview questions and additional data sources, such as staff feedback and observations, which enable us to better capture small shifts in career interests as well as big changes. #Evaluation2009 #2009Conference #Prek-12EducationalEvaluation