The scale was developed and validated with more than 3000 diverse college student samples (45% male and 55% female; 59% White, 16% Hispanic, 14% Black, 7% Asian, and 4% Other.) from 18 institutions across 15 states.  The scale contains 7 5-point likert scale items (Strongly agree - Strongly disagree)  to assess college students' openess to difference. Openness_to_Diversity_and_Challenge.pdf (centerofinquiry.org). The reported reliability is .83, which is adequate for this small set of items. 

I found that the scale is easy to administer and summarize the results of responses. But the scale is dated as it is originally developed in 1996.  The original article by Pascarella et al. (1996) have well cited for understanding students' success in college. However, the scale is not designed to measure openness to different global perspectives. Newer scales that built upon this work in the contexts of multicultural education and study aboard seem to be available and they might be a better option for specific international learning contexts.