INTERACTION D ESIGN
1 Gathering Requirements: Modeling Techniques OVERVIEW
How we model the information we
Use Cases and Essential Use cases
Task Descriptions and Task
2 U SER D ESCRIPTIONS : P ERSONAS
Rich synthesized descriptions of imaginary users but from
Allow us communicate about and understand user profiles
Capture user characteristics
Not real people, but synthesised from real user
Should not be idealised
Bring them to life with a name, characteristics, goals,
Develop multiple personas
3 T ASK D ESCRIPTIONS
an informal narrative story, simple, ‘natural’,
personal, not generalizable
As if it happened in the past – no branches (“ifs”)
assume interaction with a system
assume detailed understanding of the interaction
Essential Use Cases
abstract away from the details
does not have the same assumptions as use cases
4 S CENARIO F OR H OLIDAY PLANNER
“want to try their hand at sailing this year. There are four
members of the family: Sky who is 10 years old, Eamonn
who is 15 years old, Claire who is 35, and Will who is 40.
While out on a shopping trip they call by at the travel
agents in their local town to start exploring the possibilities
... The travel organizer is located in a quiet corner of the
agents’ office, where there are comfortable seats and play
things for young children. They all gather around the
organizer and enter their initial set of requirements—a
sailing holiday for four novices. The stand-alone console is
designed so that all members of the family can interact
easily and comfortably with it. The system’s initial
suggestion is that they should consider a flotilla holiday,
where several novice crews go sailing together and provide
mutual support for first-time sailors…” 5 U SE CASE FOR H OLIDAY P LANNER
Use Case Name Get Visa Requirements
Flow of Events 1. The SYSTEM displays options for investigating visa and vaccination
2. The user chooses the option to find out about visa requirements.
3. The SYSTEM prompts user for the name of the destination country.
4. The user enters the country’s name.
5. The SYSTEM checks that the country is valid.
6. The SYSTEM prompts the user for her nationality.
7. The user enters her nationality.
8. The SYSTEM checks the visa requirements of the entered country for
a passport holder of her nationality.
9. The SYSTEM displays the visa requirements.
10. The SYSTEM displays the option to print out the visa requirements.
11. The user chooses to print the requirements.
Precondition System displays main screen
Quality System should respond within 1 second.
Printing should be complete within 10 seconds. A LTERNATIVE C OURSES FOR H OLIDAY
Some alternative courses:
6. If the country name is invalid:
6.1 The system displays an error message.
6.2 The system returns to step 3.
8. If the nationality is invalid:
8.1 The system displays an error message.
8.2 The system returns to step 6.
9. If no information about visa requirements is
9.1 The system displays a suitable message. 7
9.2 The system returns to step 1. E XAMPLE USE CASE DIAGRAM FOR
details Retrieve visa
agent 8 E XAMPLE ESSENTIAL USE CASE FOR
Essential use cases
a. don’t specify what the involved parties exactly do.
b. don’t show the details of the interface that is used (e.g.
“provide information” instead of “display information on
USER INTENTION SYSTEM RESPONSIBILITY
find visa requirements
request destination and
supply required information
obtain appropriate visa
obtain copy of visa info
offer info in different
choose suitable format
provide info in chosen 9
format T ASK ANALYSIS
Task descriptions are often used to envision new
systems or devices
Task analysis is used mainly to investigate an
It is important to focus on:
What are people trying to achieve?
Why are they trying to achieve it?
How are they going about it?
Many techniques, the most popular is
Hierarchical Task Analysis (HTA)
10 H IERARCHICAL TASK ANALYSIS
Involves breaking a task down into subtasks,
then sub-sub-tasks and so on. These are grouped
as plans which specify how the tasks might be
performed in practice
HTA focuses on physical and observable actions
(i.e. not cognitive), and includes looking at
actions not related to software or an interaction
Start with a user goal which is examined and the
main tasks for achieving it are identified
Tasks are sub-divided into sub-tasks 11 E XAMPLE H IERARCHICAL T ASK
0. In order to borrow a book from the library
1. go to the library
2. find the required book
2.1 access library catalogue
2.2 access the search screen
2.3 enter search criteria
2.4 identify required book
2.5 note location
3. go to correct shelf and retrieve book
4. take book to checkout counter
plan 0: do