Context Diagram and Decision Table

Reference Mini Case 2 and Mini Case 3 found in your module resources. Students will submit a context diagram for the order system, and create a decision table, to be submitted as a Word document.

Decision tables and decision trees are additional tools used to decompose and visualize the logical model. A decision table is a great way to work through business scenarios. The decision tree is an aide in visualizing the decision table. In a decision table, a cross tab of condition to outcome is created. A good systems analyst relies heavily on this matrix. As the system complexity builds out, the decision table matrix serves as a reference to quickly assess an outcome. For smaller projects, an experienced systems analyst can visualize the system complexities. However, as a best practice, it is always good to document.

The decision table lists the condition on the left as a row. In practice, the row number uniquely identifies the conditions for reference in the system analysis documentation. The columns are the permutation of possible outcomes. A column condition is marked as “Y” or “N” in each permutation, or a “–” is used if the column condition does not affect the outcome. Then, by evaluating the Y/N/–combinations of a permutation column, an outcome is determined. An outcome could be “Accept” or “Reject,” or an outcome could be any number of other business processes based on the result.