top of page

Where did the Hess CRM come from?

Bloom Meets Webb: The Origins of the Hess Cognitive Rigor Matrix


The Hess Cognitive Rigor Matrices assist teachers in applying what cognitive demand might look like in the classroom and guides test developers in designing and aligning test items and performance tasks.  Content-specific descriptors in each of the CRMs are used to categorize and plan for various levels of abstraction – meaning an analysis of the mental processing required of assessment questions and learning tasks. Today many schools, states, and testing companies use these tools for professional development, curriculum work, and test item development. So where did the Cognitive Rigor Matrix come from?


The CRM began to emerge in 2005, sparked by a thoughtful question from members of a state-level committee working with me on the design of their state’s new state assessment blueprint. Like many other states, this state and their testing contractor had been using Bloom’s Taxonomy to describe test item difficulty. “Isn’t Webb’s DOK model just another way to describe the same thing as what Bloom’s six levels do?” teachers asked me when I introduced and suggested a shift to using Depth-of-Knowledge level descriptors instead of Bloom’s taxonomy as the frame of reference for determining the complexity of test items and standards they were aligned with.


I struggled at the time to clearly articulate the key differences between the two models, even though I knew they were not specifically addressing the same characteristics of complexity. On the plane home, I began to examine each model in greater depth and experimented with where the two models might intersect. Although related through their natural ties to the complexity of thought, I could see that Bloom’s thinking levels and Webb’s depth-of-knowledge levels differed in scope, application, and possibly intent. The result of my attempt to show where there was overlap was a model that superimposed Bloom's Taxonomy with Webb's Depth-of-Knowledge levels.


I started with a blank matrix template, putting Bloom’s thinking levels along the vertical axis and DOK levels across the top. At first I thought maybe Bloom’s levels of “Remember” and “Understand” might line up nicely with DOK 1; and descriptors for “Apply” might equate with DOK 2 examples. My assumption was wrong. I began to populate the cells of the matrix with specific examples, using reading and writing DOK-level descriptors that I’d developed earlier. I soon realized that I was able to identify curricular examples in language arts at every DOK level for almost every cell in the new matrix. When this approach seemed to work well for language arts, I tried applying mathematics examples, science examples, and social studies examples at each DOK level. Eureka! My idea of a cognitive rigor matrix was born. It was becoming clear to me that higher order verbs or thinking levels did not always result in learning tasks requiring deeper understanding or strategic thinking.


I still had to resolve what to put in the cells at the lower DOK levels for “Evaluate” and at the upper DOK levels for “Remember.” As I thought more about describing “Remember” in terms of depth it made no sense to put anything under DOK 2, 3, or 4. You know or remember something or you don’t. It’s as simple as that. Those cells were purposely left blank.

Deciding what to put next to “Evaluate” under DOK 1 and DOK 2 was a bit more perplexing. What do you call it when you evaluate something – state an opinion or try to make an argument – and have no supporting evidence, no elaboration, and cite no sources? Then it came to me as a flashback into my own past. These were “UGs.”  I frequently saw this notation on the early papers that I wrote while in graduate school. If Professor Bud Meyers put an “UG” in the margin, it meant that you had an unsubstantiated generalization: you stated an opinion, claim, or a “truth” but provided no credible support for it. An UG sent you back to find a source to back up your idea.

bottom of page