This paper describes three studies that were conducted sequentially for purposes of validating the Individual Sustainability survey for use with undergraduate engineering students. During the first study, researchers administered the original 50-item Individual Sustainability survey to an undergraduate engineering class at a mid-sized University, using real and ideal self. Following exploratory and confirmatory factor analysis, the survey instrument was reduced to 36 items, and reframed to compare real self to ideal professional engineer. The new version was administered to three cohorts of engineering students at the same institution, and factor structures were analyzed again. In order to provide more stable parameter estimates, a third study with 34 items was run with engineering students in similar courses at four different institutions. The methods and results of all three studies are described, to justify the survey's evolution. This is followed by a discussion of the final survey instrument and approaches for administering the survey to undergraduate engineering students, or adapting survey administration for other student populations. The instrument, in its current form, is an effective way to identify dissonance between one's real and ideal conceptualizations of self, and help individual students identify opportunities for personal change and professional growth toward sustainability values and behaviors.