Students complete design projects in order to put theoretical and technical knowledge gained from engineering science courses into practice to solve real-world problems, to expose students to industry practices, and improve their design ability (DA). If instructors were able to characterize and assess DA in students, they could optimize the learning environment to ensure learning outcomes are maximized. The existing measures of DA are performed for a limited number of students due to the time-consuming post-processing. An instrument is desired to measure DA quantitatively in order to provide immediate feedback.

This research contains 2 quantitative, 1 qualitative, and 1 mixed-methods study to produce an instrument to measure DA. The first study piloted a design scenario to measure DA. The second study developed the design scenario items and introduced qualitative items. The third study documented 9 qualities of design engineers according to professional engineers:​ collaborative, confident, creative, driven, engaged, intuitive, inquisitive, systematic and versatile. A classification of the interaction between design and engineering was produced, categorized by balance, level of tasks, and amount of design in a job.

The fourth study validated a quantitative instrument to measure DA by recording steps in a design process for a proposed design scenario. Students and professional engineers documented the steps and assigned a duration to each step. It was found that experts selected significantly fewer steps than students (p < .05), but spent significantly more time at each of the 4 major design stages (p < .001). Students and experts selected different steps, specifically for the first step. Students spent more time modelling the idea where experts spent more time in implementation. There were significant differences (p < .05) between planning and implementation among female and male professional engineers;​ female engineers spent 5 more hours planning the design whereas male engineers spent 8 more hours in implementation. After 4 studies, an instrument was successfully developed and validated to assess DA.