MANAGEMENT

6 - REQUIREMENTS ANALYSIS
• Data flow diagram. Data flow diagrams portray the movement of data through a system and how the
data is manipulated by processes. It documents where information is stored and identifies specific inputs
and outputs of processes. This documentation provides a deeper understanding of how data is used in a
system leading to identifying specific data requirements.
• Data dictionary. A data dictionary provides a description of the fields, attributes, and properties that
define the data objects relevant to the system. This structure allows information about each data element
to be documented in a consistent format. Due to the large amount of detail analyzed, data dictionaries
are used to capture very detailed requirements and their business rules that may have been overlooked
in the elicitation process.
• State table/state diagram. State tables and state diagrams document the life cycle of a data object by
defining the possible conditions or stages that the object may undergo within a solution. These models
illustrate the transition between states, the sequence in which the transition occurs, and the events that
trigger each transition.
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6.3.2.6 Interface Models
Interface models document the relationships and interactions among systems and/or users within a solution.
The following include some of the common interface models:
• Report table. A report table describes the requirements needed to develop and display information
for a single report. It defines how data is manipulated and displayed to a user. This table helps
specify the type of data that needs to be included in the report to ensure details are not forgotten
or overlooked in the solution. It provides additional details that cannot be gleaned by reviewing a
mockup.
• System interface table. A system interface table documents the communication flow and transfer of
data between the source and target systems. This includes the specific data objects, the volume of
data transferred, and the frequency of the transmission. This table is used to verify that the interface
requirements accurately describe how data will be used by the system.
• User interface flow. A user interface flow describes communication between a user and a system.
It depicts how users manipulate a system to accomplish a task. This model can be traced to other
requirements models such as process flows and individual requirements of a solution.
• Wireframe/display-action-response. A display-action-response (DAR) model documents the manner
in which a system displays data and how the system responds to actions initiated by a user. This model
is typically used in conjunction with wireframes that provide screen mockups of the user interface.
Wireframes and DAR models are helpful for identifying user interface requirements related to user actions
and system behavior.
• N2 diagram. An N2 diagram is a model, represented in a tabular format, used to identify and represent
the interfaces among elements of a system. This tool can be used to help identify and trace requirements
that affect more than one part of a system, which generally require allocation to multiple lower-level
requirements, often resulting in an iterative solution design process.
©2016 Project Management Institute. Requirements Management: A Practice Guide
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