A persistent problem in education is underrepresentation of certain cultural and linguistic groups such as American Indian, African American, and Hispanic, in special programs for exceptionally talented students, especially in science, technology, engineering, and mathematics (STEM). The spatial analytical task, a performance-based assessment with demonstrated reliability and validity as an instrument to identify exceptionally talented students, was included with new instruments created in the Cultivating Diverse Talent in STEM (CDTIS) project. A continuum of problems, including closed, semi-open, and open-ended, was an important component of the measures, enabling the assessment of creative problem solving as well as assessment of skills such as seeing how things fit together visually and in space; through mental images, on paper, and in physical objects or forms. The spatial analytical assessment was implemented as part of a battery of instruments to identify students to participate in a special internship program. Ratings of students on the spatial analytical assessment who were identified for the internship program using the new assessments were higher than ratings for students identified using conventional methods, which demonstrates that the assessment will be a useful tool for selecting students from diverse cultural groups. The assessment has multiple purposes in addition to its use as an identification tool: evaluation of special programs, planning differentiated instruction, and as a pre- and post-measure of student gains. The test-retest reliability, and construct, concurrent, and predictive validity for secondary students need continued investigation in future studies.