This article was originally posted in The SAGE Encyclopedia of Educational Technology.

In instructional design, skill decomposition is the activity of 1) first identifying the end goal of a learning event in terms of what the learner should see and be able to do as the result of the learning events and activities, and next, 2) breaking down the component skills into smaller and smaller increments of skill and attendant knowledge. The latter decomposition effort continues until the skills are at such a rudimentary level that it would be pragmatically wasted effort to continue further. Engagement in skill decomposition typically begins with a needs assessment/analysis, during which time performance challenges are identified and the gap(s) between current and desired results due specifically to insufficient skill is identified. Once the target (end) skills-focused objective(s) is/are identified, the work of decomposing, or breaking down, the skill ensues. This analysis activity and breakdown of a skill typically occur in a flowcharted format. Flowcharting software is used to build out visual representations of decomposed skills. Prioritizing skill decomposition as a central instructional design activity is key to achieving effective skills-based learning as the result. Lack of precision in this vital task will result in no clearly-defined and sequenced learning objectives, no order to the learning process, no ability to assess learning, and no effective impact on the organization. In this entry, the basics of skill decomposition are discussed, followed by a discussion of principled skill decomposition based on van Merrienboer’s 4C/ID (four component instructional design) model. A brief case-based example of skill decomposition is provided to highlight the earlier and more recent approaches.

Skill Decomposition Basic Terminology

As is the case in goal theory, one cannot move in the direction of breaking down a skill into its component parts in order to build a model of the learning design if the desired end result is left undefined. Skill decomposition begins with the identification of the end learning result, which is in the form of a behavior, or skill, that can be demonstrated. This end result is also called the target objective. Once defined, skills are broken down into their constituent human capabilities so that they can then be organized in a way that builds that end, or target objective. There are a number of human capabilities that can be combined in various ways to achieve desired learning outcomes. Such human capabilities include 1) verbal knowledge, 2) attitudes, 3) motor skills, 4) cognitive strategies, and a hierarchical building-block group of intellectual skills. Intellectual skills can be further categorized in terms  of discrimination, concrete concepts , defined concepts, rules, and problem-solving (in order of increasing complexity). The ability to decompose skills resides in a deep understanding of the meaning of each of these capabilities and the ability to break down each task – no matter how complex – into a hierarchically developed flowchart portraying human capability linkages, concurrencies, decision steps and sequences. These human capabilities, each with their capability verb used in developing learning objectives, are provided in the chart below.

Figure 1. Human capabilities and associated verbs.

Building block results

To decompose a skill, one must ask what the various human capabilities are that, when combined, will instill the target skill. As those capabilities are identified at a first lower level as enabling objectives, they must be configured appropriately according to what must be learned first, second, and so on, with each prerequisite skill being sequenced further and further to the left and down when flowcharted. Once this second level of human capabilities is flowcharted and aligned to the target objective, this level of enabling objectives then becomes a list of target objectives and the process repeats. Depending on the complexity of the skill to be demonstrated at the end of the instruction, this process can be repeated a number of times, and the flowcharting can be quite complex.

The emphasis in skill decomposition has been on demonstration of skills and affiliated knowledge and attitudes learned, but human capabilities include verbal knowledge and attitudes, both of which are not skills per-se. Through careful definition of learning objectives and decomposition of the target objective(s), it will be possible to visibly see and/or hear concrete evidence that the learner has acquired specific knowledge and/or attitude.

Decision points in skill decomposition

In addition to accurately configuring relevant human capabilities in the flowchart, decision steps are important.  Decision steps, typically portrayed in the flowchart as a diamond shape, typically asks the designer to respond to a ‘yes – no’ answering algorithm, and the flowchart arrows send the content in one of two directions.  

Figure 2. Portrayal of yes/no decision points.

Prerequisite and entry skills

Prerequisites are those skills that must be acquired before subsequent skills are instructed. Prerequisite skills are identified in flowcharts as coming from either or both the lower levels of the decomposed skill portrayal and include essential prerequisites (component skills that must be learned prior to performing the target learning objective) and supportive prerequisites (skills and related knowledge that build capacity to achieve the target skill faster, easier or more effectively.

At some point in the skill decomposition process, the instructional designer – usually with assistance from subject matter experts – determines that the target audience must enter the learning event with a minimum and specific set of knowledge, attendant skills and attitudes, per the flowcharted hierarchy of skills and as acquired during the needs assessment/analysis. The skills are usually delineated on the flowchart with a dotted line, in which those skills below the dotted line are considered entry skills.

Vertical and horizontal relationships

Vertical flowcharted relationships of skills include the target skill (at whatever level one begins) and the enabling, or prerequisite skills that feed into it from below. Horizontal relationships, on the other hand are either transposable (the ordering is inconsequential), simultaneous (one occurs at the same time as the other), and temporal (one occurs first before the next).

Skill decomposition analyses

Skills can be decomposed through a procedural, or information-processing, analysis, and through a learning-task analysis. The procedural analysis breaks down the skill into a sequential flowchart of tasks to be performed. The learning-task analysis portrays decomposition of all prerequisite skills in addition to the decomposition of the skill itself, therefore providing a clear understanding of all skills and associated knowledge and attitudes that the learner must possess at entry or that must be incorporated within the learning event to effectively achieve learning outcomes.

Van Merrienboer’s 4C/ID Model and Skill Decomposition

The 4C/ID Model specifies the process of learning complex cognitive skills. The human capabilities previously discussed serve as the framework for skill decomposition efforts, but are subsumed into declarative knowledge and procedural knowledge. Declarative knowledge includes verbal knowledge, concepts, strategies and intellectual skills that make up a sub-skill. Procedural knowledge includes the task(s) to be accomplished, very much in line with the description above of a procedural task analysis.

The 4C/ID Model most clearly specifies that the end result of learning at any level of the decomposed skill hierarchy as the demonstration of a skill package that incorporates all related knowledge, motor skills and attitudes. The model also provides a methodological framework for precise placement of decomposed recurrent tasks (tasks that always occur in basically the same manner, no matter what the circumstances surrounding it) and non-recurrent tasks (those tasks that can be more heuristic in nature), as well as just-in-time information (that information that must be provided at the specific point in time that it is required in order for the individual to be able to accomplish the task), supportive information (information supporting the learning of non-recurrent tasks) and procedural information (information that supports the learning of recurrent tasks).

Decomposition of the Skill

In this section, a target objective of skill decomposition, along with a flowcharted diagram of that decomposed skill and explanatory information to assist in understanding the decomposition process are provided to illustrate the process of skill decomposition.

As the result of this training sequence, the learner will generate a decomposed skill by flowcharting out all human capabilities in appropriate order and connections, ensuring that prerequisite skills are identified and the entry level skill set is identified. This constitutes the target objective.

Figure 3. Decomposition of the Skill.

As you can see, the diagram provides on the top row a list of steps 1-9 that would ultimately be the process being instructed. The items presented in boxes bounded by a ‘dot-dash-dot-dash’ sequence are skills that would be prerequisite to the learning of the process. The way this would be interpreted would be:

In order to achieve ‘2-ID human capabilties that enable target achievement’, one must (from bottom to top) 1) conduct a needs assessment/analysis, 2) identify all skills, related knowledge and attitudes that are present at any level of the decomposed skill, and 3) discriminate between procedural and nonprocedural skills, knowledge and attitudes.

Note that these items are bounded by a dark dotted line, below the words “Conduct needs assessment/analysis” and to the left of the ‘dot-dash’ boxes. These items would be considered entry level skills that the learner would possess prior to joining the training

Lastly, you see that   the entire process of ‘Conduct Needs Assessment/Analysis’ is bounded by the dark dotted line. The ability to do this process would also be considered a prerequisite skill and beyond the scope of learning how to decompose a skill, as portrayed in the flowchart.

See also Behavioral Task Analysis, Cognitive Task Analysis, Elaboration Theory, Four Component Instructional Design (4C/ID), Instructional Design Models, Think Aloud Protocol Analysis, Workflow Analysis,

Further Readings

Bloom, B. S., Engelhart, M. D., Furst, E. J., Hill, W. H., & Krathwohl, D. R. (Eds.). 1956. In Taxonomy of Educational Objectives: The Classification of Educational Goals: Handbook 1: Cognitive Domain. New York: David McKay Company, Inc.

Gagné, R. M., Briggs, L. J., & Wager, W. W. (1992). Principles of instructional design, Fourth edition. Orlando, FL: Harcourt Brace Jovanovich.

Jonassen, D. H., Tessmer, M., & Hannum, W. H. (1999). Task analysis methods for instructional design. Mahwah, NJ: Lawrence Erlbaum Associates.

Mager, R. F. (1984). Goal analysis (2nd ed.). Belmont, CA: Lake Publishing Company.

Reigeluth, C. M. (1999). The elaboration theory: Guidance for Scope and Sequence Decisions.. In Reigeluth, C.M. (Ed.) Instructional-design theories and models, Volume II. A new paradigm of instructional theory (pp. 425-453).

Van Merrienboer, J. J. G., & Dijkstra, S. (1997). The four-component instructional design model for training complex cognitive skills. In Tennyson, R. D., Schott, F., Seel, N.M., Dijkstra, S. Instructional design: International perspectives, Volume 1: Theory, research and models (pp. 427-445). Mahwah, NJ: Lawrence Erlbaum Associates.

Van Merrienboer, J. J. G., & Kirschner, P.A. (2007). Ten steps to complex learning: A systematic approach to four-component instructional design. New York, NY: Lawrence Erlbaum Associates.