Types of Scenario Tools

I use scenarios all the time for anything from designing a user experience to evaluating architecture. Scenario is an overloaded term though. There are lots of types of scenario tools. If you know the types of scenario tools, you can use the right one for the job. For example, exception scenarios are useful for assessing robustness.  Misuse cases are helpful for figuring out potential threats and attacks.

In the book Scenarios, Stories, Use Cases: Through the Systems Development Life-Cycle , Ian F. Alexander and Neil Maiden write about the types of scenarios and when to use them in software development.

  • Alternative World, Situation, Snapshot
  • Concept of Operations
  • Exception(-handling) Scenario
  • Negative Scenario, Misuse Case
  • Roleplay, Playthrough (of an Acted Scene)
  • Scenario Sequence, Script
  • Scripted Sequence Diagram
  • Simulation, animation
  • Story
  • Storyboard
  • Swim lanes Diagram
  • Test Case
  • Use Case
  • User Story

Here is a brief explanation of each:

  • Alternative World, Situation, Snapshot - A scenario that describes a more or less static picture of an imagined future business situation
  • Concept of Operations - A set of scenarios describing in more or less design-independent terms how a system is expected to be used in practice.
  • Exception(-handling) Scenario - A scenario that describes how to handle an undesired event.  Useful for reliability analysis.
  • Negative Scenario, Misuse Case - A scenario that is desired not to occur by the stakeholders responsible for a system. Useful for identify security threats or security issues.
  • Roleplay, Playthrough (of an Acted Scene) - A scenario acted out to illustrate a desired behavior of or a possible problem with a future System.
  • Scenario Sequence, Script - A simple list of steps ordered by time, possibly numbered, representing a Course of Events. Each step is an action taken by a named role (Actor).
  • Scripted Sequence Diagram - Shows the steps of a user with the system.
  • Simulation, animation - Narrates a scenario using images in action.
  • Story - A text that narrates a Scenario with little or no formal structure.
  • Storyboard - A sequence of diagrams or other images that narrates a Scenario.
  • Swim lanes Diagram - A flowchart arranged with a “swimming pool lane” for each role, showing both the actions of each role and interaction between roles over time.
  • Test Case - A sequence of steps to be run to verify that a system works as you intend it.
  • Use Case - A UML scenario format that consists of an Actor, a Goal, and text that contain a set of related scenarios representing different combinations of sequences of the Use Case, depending on Events.
  • User Story - A scenario format consisting of a brief, informal narrative text (a Story) that explains how a user can achieve a goal.