To begin with

Dr. Norman Webb defined four hierarchical levels of organizational complexity to encompass how deeply a student needs to understand the content in order to respond to assessment items. The central idea being that deeper levels of understanding are reflected in increased levels of complexity and the created structures students use to respond.

These four levels build upon each other. Each offers more variation and richer forms in both the manipulation and expression of knowledge.

1. Recall (or Recognition)

   "of a fact, information, concept, or procedure."

2. Basic Applications

   "use information, conceptual knowledge, follow or select appropriate procedures, with two or more decision points along the way, routine problems, organize or display data."

3. Strategic Thinking

   "requires reasoning, developing a plan or sequence of steps to approach the problem, requires some decision making and justification, abstract and complex with often more than one answer."

4. Extended Thinking

   "an investigation or application to real world, requires time to research, think, and process multiple conditions of the problem or task, non-routine manipulations across disciplines / content areas / multiple sources."

A Less Gentle Introduction

DOK-1: "Recall or recognize of a fact, information, concept, or procedure."

Consider DOK-1 as defined above. Most would quickly regard each of the four stated topical areas as quite different and even possessing some sense of implied differences in difficulty. However, it is important to note that rigor and difficulty are not the same thing. For example, compare the two following prompts:

1. Who wrote the story “Green Eggs and Ham?
2. Diagram the complete cycle that includes both condensation and transpiration.

Of these two prompts, it may appear that the second should represent some "higher level" response. Yet, DOK-1 clearly allows for recalling concepts and general information, or executing simple procedures. In both cases, the prompts asks students to respond by retrieving some piece of information. No requirements exist to manipulate, extend, or transform those items into something new. From a complexity point of view, both prompts represent very linear organizational structures with the prompt acting as a clear starting point and ending with a single expected response such as "Dr. Suess" or "a weather cycle diagram" respectively.

Borrowing some techniques from philosophy, our DOK-1 example transforms into a little diagram where the question becomes the starting prompt (IN), the response becomes the ending point (OUT), and both connect directly through a simple process.

The image helps to illustrate the natural flow of DOK-1 items. These are short, uncomplicated connections between prompt and response with no additional demands in terms of processing or manipulations. This is one of those fundamental differences between Bloom's Taxonomy and depth of knowledge. Depth of knowledge wraps the entire prompt-to-response cycle; while, various Bloom's categories might activate during that same cycle. In the above example prompts, this is particularly true for Bloom's.

So, moving along to DOK-2

Extending the model for DOK-2

DOK-2: "Basic application of skill or concept – use information, conceptual knowledge, follow or select appropriate procedures, with two or more decision points along the way, routine problems, organize or display data."

At this point, the second level of depth of knowledge requires a student to do more than simply recall. Students need to employ more sophistication by connecting dependent events to reach the final output. For example look at the following prompt.

3. Classify the characters, places, and things in the story "Green Eggs and Ham" using the provided table.

In the above prompt, a student not only needs to recall some information but needs to work with that information in some way to produce the response. What the student does with that information is constrained by the requirements of the provided table. Extending the logic model to account for these required actions, we add segment "A" to represent the two or more dependent decision points along the way as described in the definition.

For a brief moment, step back and reconsider prompt "B" from the DOK-1 examples: Diagram the complete cycle that includes both condensation and transpiration?

Why would that remain at DOK-1 even though the definition for DOK-2 includes displaying data; and, isn't drawing a diagram basically displaying data?

The distinction lies in DOK-2 requiring dependent decision points in the application of a concept or skill to obtain the final output. In other words, transforming that original concept or procedure through dependent processes into something new. The prompt used in example "B" involved no such requirement and consequently remains at the lowest DOK level.

However, the DOK-2 example in Prompt (c) requires the student to extract information then process that in accordance to the criteria of the provided table. The table might focus on the use of color, or relative size, or alphabetized spelling, or any other attribute recognizable by students. This increases the overall cognitive demand. The second level in depth of knowledge has students chaining together a series actions dependent upon prior actions as part of the process manipulating and expressing information to ultimately arrive at the final outcome. In this case, we use the term action to refer to a cognitive process or thinking event which is better described in terms of Bloom's taxonomy.

Before moving on to DOK-3, we should note that some activities and learning at a DOK-2 level involves conceptual understanding, such as what happens when students develop representations for a class of problems, ideas, objects, and so on. This is due to the fact the DOK-2 requires the student to transform, manipulate, or alter the context of information along the way to the outcome.

So, moving along to DOK-3

Extending the model for DOK-3

DOK-3: "requires reasoning, developing a plan or sequence of steps to approach the problem, requires some decision making and justification, abstract and complex with often more than one answer."

While DOK-2 allowed for the inclusion of multiple actions, these were directly dependent upon each other and tightly constrained to the outcome. Under DOK-3, students have a choice in how to pursue their actions toward the final outcome. The use of decision making and justification represents alternative paths in manipulation and expression of information to achieve some new outcome. Consequently, with more options available more possibilities exits in terms of outcomes.

For example:

4. Using evidence from the story, what reason would the author choose green for the color of the eggs and ham?

For DOK-3, the logic model needs to account for two or more possible paths of dependent decision points along the way. Additionally, the final response might have one or more correct outcomes. This produces the following:

Depth of Knowledge three represents the first time where the possibility of multiple correct outcomes occur. This possibility relates directly to the expansion in the available decision paths along the way from the starting prompt until the final outcome. However, please note that multiple outcomes is not a requirement but simply an allowance. The core distinction in DOK-3 lies in the more complex decision paths available; these paths are the linked to alternative choices in how to work through the process to produce an outcome. While DOK-2 required a single path of dependent decision points, DOK-3 ups the ante by requiring at least two distinct paths each with their own set of decision points.

Cognitively, this creates opportunity to move through information based on less concrete aspects; such as, contextual relationships, linked or similar concepts, and trying forward looking scenarios for instance. Working at this level of Depth of Knowledge means a student has the ability to reorganize, re-purpose, and re-conceptualize knowledge in-process to achieve an intended goal.

So, moving along to DOK-4

Extending the model for DOK-4

DOK-4: "an investigation or application to real world, requires time to research, think, and process multiple conditions of the problem or task, non-routine manipulations across disciplines / content areas / multiple sources."

The DOK-4 level describes the last level of complexity in the hierarchy. It opens the field of possibilities widest by exposing the prompt itself to manipulation. By processing multiple conditions of the problem, DOK-4 sets the stage for students to qualify the context of the entire prompt-to-response cycle according to their own self-directed purposes.

For example:

5. Dr Seuss was known for using a 50-word vocabulary to write his stories. Create a small story of your own using words from the same 50-word vocabulary as Dr Seuss.

The critical point behind DOK-4 revolves around the open-ended nature it embodies with multiple potential starting points, many possible outcomes, and scores of decision paths in between those. The logic model needs to incorporate these aspects. Fortunately, this is rather straightforward by allowing the prompt to have more than one possibility.

Operating at the DOK-4 level means students have the ability to conditionally filter, pre-process, determine the validity or usefulness of information at the beginning of a larger project in the context of a planned or self-directed outcome. Additionally, students must determine appropriate solutions paths and make choices that facilitate progress. DOK-4 defines a rather fluid ability to move through information, procedures, and abstract relationships choosing and making connections as needed to achieve goals.

Quick recap on using DOK

Let's take a moment to collect all this together. Depth of Knowledge in its four hierarchical levels describes increasing degrees of organizational complexity. These in turn offer more variation and richer forms for both manipulation and expression of knowledge. From the logic diagrams, we can see how DOK increases in both complexity and its ability to describe the orchestration of cognitive processes.

Even though Depth of Knowledge looks at the underlying sophistication within a response, it reflects extremely well back into instruction. Cognitive Rigor (juxtaposition between Bloom's Taxonomy and Depth of Knowledge) capitalizes on this fact. Using Depth of Knowledge as the structural framework to orchestrate cognitive actions, instruction can take advantage of this to better position use of strategies, activities, and modes of thinking which rely upon Bloom's more readily.

• DOK-1: Use for simple procedural activities, probing questions, and etc.
• DOK-2: Use for simple linear activities that transform information with a well defined outcome.
• DOK-3: Use for activities with a clear starting point that incorporates some alternative solution choices that ends in at least one acceptable outcomes.
• DOK-4: Use for broad long-term activities requiring discovery, organization, filtering, and informed decision-making resulting in a variety of acceptable outcomes.