
Cognitive rigor plays an especially important part in developing twenty-first skills. Incorporating higher levels of Bloom's Taxonomy in questioning enhances thinking skills, while assigning activities aligned with higher depth of knowledge (DOK) levels promotes strategic skills in planning, organizing, and structuring. Through the analysis of completed student work, Ruby can pinpoint areas of concern and potential improvement in regards to cognitive rigor.

The chart above could point to a serious deficiency in a school's efforts to teach 21st-century skills. A predominance of low-level assignments (as evidenced by the dark region in the lower-left corner of the figure and the overwhelming percentage corresponding to Level 1 of depth of knowledge) is especially troublesome in science, a field that provides ample opportunities to teach higher-order thinking skills. Professional development in curricula rigor could increase the twenty-first-century skills of students attending this school.