The Depths of Knowledge (AKA DOK) is another measurement of student thinking for academic planning. That is to say, like Bloom's Taxonomy, the DOK "ranks" tasks and activities students can do as either higher-order thinking or lower-order thinking.
While Bloom's is ranked in six categories, lowest to highest, remembering, understanding, applying, analyzing, evaluating, and creating, the DOK streamlines these into four categories: recall/reproduction, skill/concept, strategic thinking, and extended thinking. While the difference may seem inconsequential, the DOK tends to allow for more overlap in its categorization to account for higher order and lower order tasks that use the same methods. For instance; identifying the transitions in a paragraph is not particularly rigorous. Identifying the kinds of rhetorical devices used in a political campaign speech and the effect they have would be more complex. Both involve "Identification" but at different levels. Likewise, creating a poster with a definition on it is not the same as creating a detailed model of a scene from the book with characters strategically placed based on descriptions from the text, with character models based on researched knowledge from the time period.
The DOK is also shaped like a wheel. This implies that while some tasks may be more rigorous than others, that does not necessarily mean the lower orders are inherently useless. When beginning to teach a skill or concept, they are necessary for students to acquire the skills that will allow them to learn more later.
Recall includes less intensive skills like memorizing, restating, recognizing, describing, etc. Stuff that is useful, but not at all labor intensive or rigorous. Recall-level activities include quizzes, workbooks, worksheets, and reciting.
Skill/concept includes actually applying knowledge to a task. If the kids have memorized a set of rules or steps, now they actually do it. If they have learned what essay structure is and how to identify essay parts, now they are writing an essay with that knowledge. If there is identification, it is more complex with more explanation and exploration of concepts. The tasks here are more rigorous that the previous tasks.
Strategic Thinking tasks are tasks wherein students are more analytical and evaluative in their approach to a problem or task; they know how essay structure works, now they must expand that knowledge not just in writing a five paragraph essay, but in exploring how other people structure their papers, how those papers can be structured in another way, and to what affect. Here is also where you get more rigorous "why?" questions. Why does that character act that way? Why did the author choose to include this scene?
Extended Thinking involves synthesis (more creation), assessment, and adjustment over longer periods of time. Here is where long, thoughtful projects with a lot of retooling comes in. The process of learning in these projects is learning in and of itself, causing students to design and plan and redo their plans. These assignments are usually very complex and require several steps to complete. This is also where drafted, detailed character analysis essays come in, or those argumentative research papers where you have to debate your point.