RE: Scenarios, Tasks, Use Cases, User Profiles/Personas, etc.

I'd like to echo Tim's reference here. I think we should not try to 
redefine use case and user scenario but use the definitions that are 
defined by UML. We refer to the following definition of a use case in our 
testing guidelines:

A use case tells a story about: 
How a user uses the system to fulfill some need 
Achieving some goal 
What the system does to satisfy that goal 

Use cases:
Describe the sequence of interactions between actors and the system needed 
to deliver the service that satisfies the goal.
Decide what the system will be used for before defining what the system is 
supposed to do. 

Use cases capture: 
who (actor) does what (interaction) with the system 
for what purpose (goal), without dealing with system internals

We define a scenario as follows:
Scenarios define different ways of reaching the goal or different flows 
through the system. Say for example, a use case is a student registering 
for a course. Some different scenarios might be: a successful 
registration, unknown student, student quits registration process, student 
cannot enroll. 

Found the following definition of scenario in this white paper by SHINPEI 
OGATA and SAEKO MATSUURA 
http://www.wseas.us/e-library/conferences/2010/Cambridge/SEPADS/SEPADS-25.pdf 

 
Scenarios "describe normal, alternative, and exceptional service flows 
from the point of view of system usage." 

Moe

Maureen Kraft
Accessibility Consultant Test Lead
Human Ability and Accessibility Center 
IBM Research 
E-mail: maureen_kraft@us.ibm.com 



From:   "Boland Jr, Frederick E." <frederick.boland@nist.gov>
To:     Michael S Elledge <elledge@msu.edu>, "public-wai-evaltf@w3.org" 
<public-wai-evaltf@w3.org>, 
Cc:     Sarah Swierenga <sswieren@msu.edu>
Date:   04/10/2012 12:07 PM
Subject:        RE: Scenarios, Tasks, Use Cases, User Profiles/Personas, 
etc.



Thanks! In addition, I found the following link to a definition for use 
case:
http://www.wordiq.com/definition/Use_case

Best, Tim Boland NIST 

-----Original Message-----
From: Michael S Elledge [mailto:elledge@msu.edu] 
Sent: Tuesday, April 10, 2012 11:58 AM
To: public-wai-evaltf@w3.org
Cc: Sarah Swierenga
Subject: Scenarios, Tasks, Use Cases, User Profiles/Personas, etc.

Hi Everyone--

Eric asked me at last week's meeting to put together a definition of what 
we call scenarios and how they fit in our usability evaluation process, 
since there are parallels to what the task force is describing for 
methodology.

Some background first. In a usability test, we ask people, one at a time, 
to find specific information that is contained on a website. 
Finding each piece of information is called a task (there may be 8-10 
tasks in a usability test) and requires a participant to proceed through a 
number of steps in the website. We observe the person to identify if they 
have been successful finding the information, how long it takes, the path 
they take to find the information and any errors they make along the way. 
Either at the end of each task or at the conclusion of all the tasks, we 
ask about their experience with respect to navigation, labeling, 
comprehension and satisfaction. This information is then used to make 
suggestions of how to improve the website we are testing.

These are the elements of the process and our definitions.

User Profile--This is the type of person we want to include in testing and 
is used for recruiting participants. It will have information about age, 
gender, experience using the website and the Internet in general, and 
other criteria that define them as one part of the website's target 
audience.

Persona--Personas in our experience are more complete representations of 
the website's target audience, including their attitudes, experiences, 
objectives in using the website, specific tasks they want to accomplish, 
as well as the demographic elements in a user profile. There will be 
multiple personas for each site. Personas are often used to help website 
designers and developers have a shared understanding of what people want 
to do with the website so the navigation, labeling, and aesthetics will 
meet their needs.

Use Case--A use case would be a description of what a particular person 
wants to accomplish on a website in a particular situation. It's analog in 
user testing is a scenario plus a related task.

Scenario--We use a scenario to set the context for a usability test. It 
describes the situation for a participant and sets the stage for 
subsequent tasks. For example, if we were evaluating the Metropolitan 
Transportation Authority website: "You are traveling from Manhattan to 
Westchester County to visit family. Your family lives in New Rochelle."

Task--Tasks are the specific activities that we want participants to 
attempt. They follow the scenario. There may be 3-5 for each scenario. 
So an example might be: "You are leaving on a Friday and returning Sunday. 
Find the times available for you to travel."

I help this is helpful. Other people on the list may have somewhat 
different definitions depending on their design and development process.

Mike

--
Michael S. Elledge
Associate Director
Usability/Accessibility Research and Consulting Michigan State University 
Kellogg Center
219 S. Harrison Rd Room 93
East Lansing, MI  48824
517-353-8977