- The Seven Basic Principles
- Scope of Subject Matter That Can Be Handled by IDEF0
- Benefits Resulting from the Use of IDEF0
- Features of IDEF0 Analysis
- Comparison to Data Flow Diagramming
- Understanding a Top-Level IDEF0 Diagram of an Enterprise
- Levels of Abstraction in IDEF0 Models
- The Role of Data Analysis Compared to IDEF0 Function Analysis
Features of IDEF0 Analysis
The IDEF0 method analyzes a subject by investigating how it operates, by modeling the operational details uncovered, and by applying evaluation techniques (such as “value added” criteria) to identify potential improvements. The author of the model uses two-dimensional, simple graphics as a means of capturing and communicating the results of the analysis.
Applying IDEF0 to the analysis of an enterprise thus results in a paper, two-dimensional graphical model of the enterprise. The model is hierarchical in nature, consisting of a set of diagrams in which each diagram represents three to six activities of the enterprise. At the top of the IDEF0 model, the enterprise is decomposed into three to six very large activities or subsystems that represent the activities of the enterprise (see Figure 3-1). These activities are shown as rectangular boxes.
Figure 3-1: Breakdown into Six or Fewer Activities.
Once the top-level activity breakdown has reached consensus among the enterprise staff, each of the boxes is further broken down into the next level of detail on a new three-to-six activity diagram. Thus, the entire IDEF0 model provides a tree structure of diagrams. Anyone wishing to inspect a particular aspect of the enterprise may scan the tree structure, identify the activity and level of detail that is useful for his purposes, and then retrieve the corresponding IDEF0 diagram to study the complete description of the selected activity at the selected level of detail. Figure 3-2 shows a graphical representation of an IDEF0 model that breaks down an enterprise into three levels of detail.
Figure 3-2: Top-Down IDEF0 Model Structure.
At the top level, the entire system being modeled (labeled Whole System in the figure) is shown as broken down into four parts, labeled 1, 2, 3, and 4. Part 2 is further broken down into a three-part diagram, shown below the initial diagram as emanating from a shaded box 2. Finally, boxes 1 and 3 of the detailed part 2 box are broken down into yet finer detail in the two diagrams displayed at the bottom of the figure. This illustrates an important feature of the IDEF0 model: Any aspect may be broken down to be as detailed as necessary, while other aspects may be less completely decomposed. This permits the analyst to zero in on the most critical aspects to be analyzed, while putting off the other aspects until needed.