The main purpose of this study is to measure changes in students' perception on their problem solving ability over time by using Rasch Measurement Model. Pre-experimental with one group pretest-posttest design was conducted to investigate how web-based learning system of design education, known as PROUD, affected students' perceptions of their problem solving ability. Thirty second-year students pursuing their bachelor degree in technical and vocational education participated in the study. Respondents utilized PROUD for 14 weeks in the process of learning design. Problem Solving Inventory was used as a research instrument and appeared valid and reliable to measure the changes. A pretest was administered at the beginning of the course and a posttest after the learning completed. Changes in the students' perceptions of their problem solving ability were gauged using the rack and stack analysis. A paired sample t-test was also included in the data analysis. The result of the pretest and posttest were -0.147 +/- 1.554 logits and -0.749 +/- 0.980 logits, respectively. These findings indicate that the perceptions of the students on their ability to solve problems have increased significantly after using the PROUD (paired sample t-test, p = 0.032). These have proven that the use of PROUD changes the students' perception on their problem solving ability throughout the learning process of design.