Background:
This article reports contributions of an assessment tool called Portfolio of Evidence (PE) in learning college geometry.

Material and methods:
Two classes of second-year students from one Ethiopian teacher education college, assigned into Treatment and Comparison classes, were participated. The assessment tools used in the Treatment and Comparison classes were PE and paper-and-pencil, respectively. Data sources were scores of: Self-/Teacher-Assessment Rubric (STAR); Mathematical test measuring Skills, Properties, Uses, and Representations (SPUR); and Learning and Study Strategies Inventory-High School Version (LASSI-HS).

Results:
Comparison of students’ Self- and Teacher-Assessment data showed that students in the Treatment Class were able to assess their own learning and progress as authentically as the teacher. Analyses of SPUR data revealed that the learning gains among the students in the Treatment Class were significantly greater than that of the Comparison class in tests requiring higher order thinking (p ≤ 0.05). Analyses of LASSI-HS showed that students in the Treatment Class made more statistically significant shifts towards demonstrating supportive learning behaviors and towards abandoning inhibiting behaviors than those in the Comparison Class (p ≤ 0.05).

Conclusions:
Thus, effective integration of PE in the instructional process helped students develop reflective thinking and other metacognitive skills and solve real-life problems that demand higher order thinking.