Some Basic Differences Between a Procedural Task Analysis and a Hierarchical Analysis
1. A hierarchical task analysis (also known as a prerequisite task analysis) answers the following question: "What must the learner know or be able to do to achieve this task?"
2. A procedural task analysis (also known as an information-processing analysis) answers the following question: "What are the mental and/or physical steps that the learner must go through in order to complete this task?"
3. A hierarchical task analysis is developed bottom up, from general to specific.
4. A procedural task analysis is developed linearly and sequentially, step-by-step. It has a directional flow. It has a start and a an end.
5. A hierarchical task analysis is based on learning taxonomies, starting from the most complex (e.g. problem-solving in Gagne’s cognitive taxonomy of learning) to the least complex (e.g. verbal information in Gagne’s taxonomy). The nature of the terminal task determines at which level in the taxonomy one should start breaking down the task from more complex to less complex, going through each of the learning levels.
6. A procedural task analysis is not concerned with the levels of the learning taxonomies, it is procedural in nature. If the task is a relational rule, then the steps of the task analysis would include "how to apply this rule". If the task is concept learning, then the task analysis would include "how to determine whether a particular instance (occurrence) is an example of this concept". Review examples on pages 75-84 in Smith & Ragan.
7. A hierarchical task analysis is represented in terms of levels of tasks. Each level should (more or less) represent one learning level (e.g. problem-solving, concept learning, etc.). The highest level is the most complex. Lower levels form prerequisite skills for higher levels. Lines connect tasks between levels. Each task can be broken down into one or more tasks from one level to the next.
8. A procedural task analysis is represented in the form of a flowchart or an outline. If a flowchart is used, then lines with arrows connect tasks. The direction of the arrows indicates the sequence of the steps (tasks). Diamond shaped decisions symbols indicate a change in direction depending on the outcome. If an outline is used, the steps in the outline are numbered to indicate the sequence. Subtasks are also numbered to indicate the flow within a larger task.
9. A hierarchical task analysis is read bottom-up. If we were to put arrows on the lines that connect the tasks they would be pointing upward, towards the terminal task.
10. A procedural task analysis is read from left to right or from top to bottom (following the direction of the arrows if in flowchart form, or the numbering of the steps if in outline form).
11. In a hierarchical analysis, each task is a prerequisite to the task directly above it. Tasks that can happen concurrently with other tasks should be on the same level in the hierarchy.
12. If using a flowchart format to do a procedural analyis, you can break down some of the tasks within the flowchart into an outline format if those tasks have subtasks.
13. In a hierarchical analysis, list all your givens or assumptions as prerequisites at the very bottom of the hierarchy.
14. In a procedural analysis, you must always have a START and an END, all tasks must be connected using arrows, and decision symbols can only have a YES/NO going out.