Agile Models: Potential Agile Modeling Artifacts

This page provides a brief summary of potential models that you may choose to apply when developing business application software. This list is not complete, there are undoubtedly hundreds of types of artifacts available to you, but it does describe ones that are common use for modern software today. Furthermore, the focus is on the development of business application software not other types such as embedded software or system software. Yes, many of the artifacts could and should be applied in these other domains but the chart reflects a methodology geared for the development of modern-day business software. Finally, it is important to understand that you very likely won’t need to apply every single technique on any given initiative, instead you will want to apply a subset that is appropriate to the task at hand.The table below is large, sorry about that, and it may not contain everything that you need (such as a detailed description of the notation) which is why I include links to good references that describe the technique. For now you may want to refer to the Agile Models Distilled pages. Artifacts are listed in alphabetical order, links to detailed descriptions of each artifact are provided, and an explanation of the columns are at the bottom of the page. You may also want to refer to the article Be Realistic About the UML.How does this chart support Agile Modeling (AM)? The principles Multiple Models indicates that you potentially need a wide range of models available to you, Know Your Modelsadvises that you need to understand the strengths and weaknesses of each technique to apply them appropriately, and Content is More Important Than Representation implies that many artifacts have alternates that may be applicable for your situation. The practices Create Several Models in Parallel and Iterate to Another Artifact also require you to understand when and when not to apply a modeling technique, and Discard Temporary Models requires advice pertaining to when you should keep an artifact.

Artifact	Common Applications	Common Misapplications	Iterate To	Suggested Media	When to Keep It	Likely Value as Keeper	Alternate/Similar Artifact	Also Known As
Activity Diagram (UML)	Analysis or design of a business process or business rule Design of the logic flow of a complex operation	–	Class diagram Business use case Organization chart Source code System use case Usage scenario Use case diagram User story	Hand-drawn sketchDrawing tool CASE tool	To provide a high-level overview of the logic for a business process	Low	Data flow diagram Flow chart Specification language Workflow diagram	–
Business Rule Definition	Requirements identification	Documentation of technical requirements	Source code Class diagram CRC model Business use case Flow chart System use case Usage scenario Workflow diagram	Index cardWord processor	When exact definition of business rules are required in a stakeholder-readable format.	Medium	User story Source code	Shall statement
Change Case	Exploration of future potential requirements	Justification to overbuild software to meet “potential” requirements	Constraint CRC model Technical requirement Usage scenario Use case User story Workflow diagram	Index cardWord processor	When you need to justify design or architecture decisions to stakeholders AND they require documentation	Low	–	Future requirements Architectural requirements
Class Diagram (UML)	Conceptual modeling Domain modeling Exploration of the structure of object-oriented software	Physical database modeling Domain model documentation for users Only design diagram for OO software	Activity diagram Collaboration diagram Component diagram CRC model Data model Sequence diagram Source code State chart diagram Usage scenario User story	Hand-drawn sketchCASE tool	You need to communicate the internal structure of your software to others.	Low	Class Responsibility Collaborator (CRC) Model	Object model
Class Responsibility Collaborator (CRC) Model	Domain modeling Conceptual modeling Exploration of the design of the structure of object-oriented software	–	Business rule Change case Constraint Class diagram Business use case Organization chart System use case Usage scenario Use case diagram User story	Index card	Typically discarded after use.	Very Low	Class diagram	CRC cards Index cards
CommunicationDiagram (UML)	Exploration of the dynamic nature of complex object interactions	–	Class diagram Component diagram Deployment diagram Robustness diagram Source code System use case Usage scenario User interface flow diagram User interface prototype User story	Hand-drawn sketchCASE tool	Typically discarded after use May be kept to show design of a complex portion of software	Very Low	Sequence Diagram	Interaction diagram
Component Diagram (UML)	Logical business architecture modelingPhysical architectural modeling of a component-based software system		Class diagramDeployment diagram Sequence diagram	Hand-drawn sketchCASE tool	Often kept to depict high-level architecture	High	–	–
Constraint Definition	Definition of a business or technical constraint	Definition of a Business rule Definition of a technical requirement NOTE: There’s a fuzzy line between constraints and business rules as well as with technical requirements	Change case CRC model Deployment diagram Business use case System use case Technical requirement Usage scenario Workflow diagram	Index cardWord processor	Kept as part of official definition of requirements	Medium	User Story	Shall statement
Data Flow Diagram (DFD)	Analysis of existing business processes Design of new or updated business processes	Over specification of a system by “drilling down” into sub processes with more DFDs. Significant effort to level balance between a DFD and its sub-DFDs	Change case Constraint Data model Deployment diagram Organization chart Structure diagram System Use case Usage scenario Use case diagram User story Workflow diagram	Hand-drawn sketchDrawing tool CASE tool	To communicate overall design of a process-intensive system	Low	Activity diagram Workflow diagram	Process model
Data Model	Physical database design Conceptual or domain modeling for a data warehouse Explore relationships between a handful of entities	Conceptual modeling of OO software Domain modeling for OO software Exploration of structure of OO software A primary driver of the structure of a Class diagram	Class diagram Data flow diagram Deployment diagram Source code System use case Usage scenario User story Workflow diagram	Hand-drawn sketchCASE tool	To document physical database design As a contract model between the database owners and other systems accessing the database	Very High	–	Persistence Model Entity-Relationship Diagram
Deployment Diagram (UML)	Identification of physical architecture for a system Identification of how software components are and/or will be deployed to physical architecture	?	Activity diagram Collaboration diagram Component model Constraint Data model External interface specification Sequence diagram Usage scenario User story Workflow diagram	Hand-drawn sketchCASE tool	To document technical architecture of your system	Medium	Network Diagram	–
Business Use Case	Identification of usage requirements for a system Identification of enterprise-level requirements for an organization	–	Change case Constraint Low-fidelity interface flow prototype Robustness diagram System use case Technical requirement	Word processorCASE tool	Part of official requirements documentation for a system	Medium	Usage scenario User Story
Low-Fidelity Interface Prototype	Exploration of the requirements for the user interface of a system	–	Business rule Constraint Business use case User interface flow diagram User interface prototype	Paper (including Post-It notes)Hand-drawn sketch	Typically discarded	Very Low	–	Abstract prototype Low-Fidelity Prototype
External Interface Specification (Contract Model)	Definition of interface (via an API, data feed, …) to an external system	?	Data flow diagramData model Deployment diagram Workflow diagram	Word processorCASE tool	As a contract model between your system and an external one	Very High
Features	Exploration of requirements	?	Acceptance test case Business rule definition Class diagram Class Responsibility Collaborator (CRC) model Collaboration diagram Constraint definition Essential user interface prototype Glossary Source code User interface prototype	Index card Word processor	When you need a feature list describing your system	Medium	Business rule Constraint Technical requirement User story	Shall statement
Flow Chart	Definition of complex logic	Over specification of logic when source code or specification language would do just as well	Class diagram Collaboration diagram Sequence diagram System use case Usage scenario User story	Hand-drawn sketchDrawing tool CASE tool	Typically discarded	Low	Activity diagram Specification language	–
Glossary	Definition of common terms	To much focus on getting it perfect.	Class diagramData model System use case Usage scneario	Word processor	Official definitions of terms.	Medium	–	Definitions
Network Diagram	Analysis of existing technical infrastructureDesign of proposed technical infrastructure	–	Component diagramSystem use case Workflow diagram	Hand-drawn sketchDrawing tool CASE tool	Official description of technical infrastructure for your system or organization	High	Deployment diagram	Technical Architecture Diagram
Object Role Model (ORM) Diagram	Exploring domain concepts with stakeholdersConceptual modeling	–	Data modelUML Class diagram	Hand-drawn sketch	Official conceptual model for your system	Low	CRC model Data model UML Class Diagram	–
Organization Chart	Depiction of existing or proposed organization structure	–	Activity diagramClass Responsibility Collaborator Model Data flow diagram Use case diagram Workflow diagram	Index cards & stringHand-drawn sketch Drawing tool	Official description of the organization structure of your enterprise or portion thereof	Medium	None	None
Package Diagram (UML)	High-level overview diagram that depicts the logical organization of requirements or a domain modelHigh-level overview diagram depicting the physical organization of classes into packages To organize work, such as the assignment of requirements to specific subteams	–	Class diagramUse case diagram	CASE toolIndex cards Hand-drawn sketch	When a CASE tool diagram is used to generate code into specific packagesAs an overview diagram depicting the organization of requirements	Medium	Component diagram	Logical Package Diagram
Physical Prototype	Explore ergonomic issues of a system	–	Activity diagram Deployment diagram Network diagram System use case Usage scenario User story Workflow diagram	–	Typically discarded	Very low	–	–
Robustness Diagram	Analyze use cases to identify candidate classes and major user interface elements (screens, reports, …)	To design user interface flow for a system To design static structure of OO software	Collaboration diagram Sequence diagram System use case Usage scenario User interface flow diagram User interface prototype User story	Hand-drawn sketchCASE tool	Typically discarded	Low	–	–
Role Play	Exploration of the usage requirements for a systemVerification that a system design will meet the needs of its users	–	Business rule Change case Constraint Business use case System use case Technical requirement Usage scenario User interface flow diagram User interface prototype User story	–	N/A	N/A	–	Play acting
Sequence Diagram (UML)	Modeling the logic of a usage scenario or a path though one or more use cases (or part(s) thereof)	Modeling of the logic for every single path through all the usage requirements for your system	Class diagram Robustness diagram System use case Usage scenario User story	Hand-drawn sketchCASE tool	Typically discarded	Very low	Collaboration Diagram	Interaction diagram
Specification Language (e.g. OCL)	Define precise logic of a process, operation, constraint, or business rule	Over specification on diagramsDetailed documentation for stakeholders that likely don’t understand the language	Business rule Class diagram Collaboration diagram Component diagram Dataflow diagram Workflow diagram	CASE tool Word processor	Part of your official definition of requirements	Medium	Activity diagram Flow chart	–
State Machine Diagram (UML)	Design the behavior of a complex class Analyze a complex business process	Design the behavior of several classes Model process flow Design the behavior of a simple class and/or one without interesting behavior based on state	Business rule Class diagram Source code System use case Usage scenario Table	Hand-drawn sketchCASE tool	May be kept as part of your design documentation for complex class or process	Low	–	State diagram Statechart State transition diagram Petri nets
Structure Diagram	Explore the “call” hierarchy within the design of procedural software	Design of object-oriented software	Dataflow diagram Source code	Hand-drawn sketch	High-level design of structured software	Low	Collaboration diagram Sequence diagram	Call diagram Structure chart
System Use Case	Analysis of usage requirements High-level design of implementation of usage requirements	Identification of usage requirements for a system The ONLY source of system specification for a system (e.g. you should avoid use-case driven [INSERT TERM HERE])	Collaboration diagram Business use case Flow chart Robustness diagram Sequence diagram State chart diagram Usage scenario Use case diagram User interface prototype	Word processorCASE tool	Part of your design documentation for your system	Low	Usage scenario User Story	Traditional Use Case
Table	Definition of complex business rules, constraints, or technical requirements	?	See business rules, constraints, & technical requirements	Word processor	Part of your official requirements definition	Medium	–	–
Technical Requirement	Requirements identification	Identification of business requirements Identification of “gold plate” requirements that the technical staff want to implement	Change case Constraint Deployment diagram Network diagram Workflow diagram	Index cardWord processor	Part of your official requirements definition	Medium	–	Non-Functional Requirement Shall statement
Use Case Diagram (UML)	Overview diagram indicating major usage requirements Analysis of usage requirements of an existing system	Process diagramming Diagramming without supporting use cases	Activity diagram Data flow diagram Business use case Organization chart System use case	Hand-drawn sketchDrawing tool CASE tool	Overview of your usage requirements	Medium	–	–
Usage Scenario	Exploration of the usage of a system	?	Activity diagram Business rule Constraint Deployment diagram Flow chart Network diagram System use case Workflow diagram	Index cardWord processor	Typically discarded	Very low	System Use Case User Story	Use case scenario
User Interface Flow Diagram	Exploration of user interface requirements High-level design of an application’s user interface	?	Business use case Robustness diagram System use case User interface prototype User story	Hand-drawn sketchDrawing tool CASE tool	Part of official design documentation to provide overview of your user interface design	Medium	–	Interface flow diagram User interface navigation diagram
User Interface Prototype	Detailed design of a user interface	ONLY source of system specification Identification of user interface requirements ?	Business rule Constraint Business use case Robustness diagram Source code System use case User interface flow diagram Workflow diagram	Hand-drawn sketchUser interface prototyping tool	Typically discarded or evolved into working system	Low	–	–
User Story	Exploration of usage requirements Reminder to have a conversation with a stakeholder	?	CRC model Collaboration diagram Deployment diagram Robustness diagram Sequence diagram Source code Workflow diagram	Index cardWord processor	Typically discarded	Very Low	Business Rule Constraint Essential Use Case System Use Case Use Case Scenario	–
Workflow Diagram	Analysis of existing business processDesign of new business process	ONLY source of system specification?	Business rule Change case Constraint Deployment diagram Organization chart System use case Usage scenario User story	Hand-drawn sketchDrawing tool CASE tool	Part of your design documentation describing the supported business processes	Medium	Activity diagram Dataflow diagram Control flow diagram	Coats-Mellon Notation

The Columns:

Artifact. The name of the modeling artifact.
Common Application. Common uses for the technique when developing business applications.
Common Misapplication. Common misuses of the technique that often lead to busy work or rework because the concept could be better captured using another technique. This column also includes advice for when not to apply the technique.
Iterate to. Suggested artifacts that are good choices to work on next from this one when following the practice Iterate To Another Artifact.
Suggested Media. An ordered list media which can be used to support the technique. Note: A drawing tool is something along the lines of Visio whereas a CASE tool is more along the lines of Rational Rose or TogetherSoft’s Together.
When to Keep It. Advice for situations when it may make sense for this model to be a “keeper”. However, never forget the principle of Travel Light.
Likely Value as Keeper. A rating of the likeliness that keeping the artifact will actually prove of value to your future efforts if you do decide to keep it.
Alternate/Similar Artifact. Modeling artifact(s) that are similar in nature to this one that could potentially be used as a replacement.
Also known as. Common aliases for this artifact.
References. Books or online resources describing the technique.