A software company has won a contract to implement its product for a client.

The BA should use a sequence diagram to elicit information about the other client applications that will interface with the new system and provide the information graphically. A sequence diagram is a type of interaction diagram that depicts the interactions between objects or components in a time-ordered sequence. A sequence diagram can help the BA and the technical staff to understand the message interaction within the systems for key business transactions, as it shows the chronological order of interactions and the messages exchanged between objects. A sequence diagram can also help the BA to model the behavior of a single use case or scenario, and to identify the dependencies and constraints among the objects. Process, activity, or context diagrams are not the best options for this purpose, because they are either too general, too abstract, or not directly related to the message interaction within the systems. References:

CBAP / CCBA Certified Business Analysis Study Guide, 2nd Edition, Chapter 7: Requirements Analysis and Design Definition, page 279

Business Analysis Body of Knowledge (BABOK) Guide, Version 3, Chapter 7: Requirements Analysis and Design Definition, section 7.5: Specify and Model Requirements, page 133

Business Analysis Professional Resources, IIBA Resource Collection, Business Analysis Body of Knowledge (BABOK) Guide

CBAP / CCBA Certified Business Analysis Study Guide, 2nd Edition, Skillsoft Book, Chapter 7: Requirements Analysis and Design Definition, page 279

Interaction Diagram Tutorial, Lucidchart, What is an interaction diagram?