Interface Guidelines

Interface Guidelines & Principles
7 principles for Interface Design
Focus on the users & tasks, not technology.
Conform to the User’s View of the Task.
Consider function first, presentation later.

Function 1st, Presentation Later
Does NOT mean
Get the functionality designed and implemented first and worry about the user interface later.
The word function here refers to implementation. Get the system/prototype functioning first.
Do NOT write code before you have considered the user interface’s function.

Function 1st, Presentation Later
Does mean
What concepts will the software expose to users?
Are the concepts new, familiar?
What data will users work with?
What information does the data provide?
Where does the data come from?
What are the options the system will have?
Adaptive, personalization, direct-manipulation.
Function means Role. What is the role of the software.

Two Views of Function
User versus Designer

User Mental Model
User’s view of the system.
System and its function.
Expectations of the users.

Conceptual Model
Model of the product that the designer wants the user to understand.
Designer’s view of the product.
Expressed in terms of the concepts of the intended user’s task domain
Data and how, when, where it will be used.
In most cases, this is NOT an interface drawing.
Explains the function of the software and what people need to be aware of in order to use it.

Conceptual Model vs. Mental Model
UNIX operating system. Rename a file.
Conceptual Model is to use mv.
This moves a file, simplifies the need for another command.
User Mental Model
User wants to rename, rn or re not move the file.

Developing a Conceptual Model

1. Object/Action Analysis
Define all of the objects.
Nouns.
Define all of the actions.
Verbs

2. Lexicon or Ontology
Ontology
A common vocabulary for a specific domain.
Learn the users’ vocabulary and introduce yours.
Agree upon a common use of terms.

3. Scenarios
Task Scenarios
Scenario development
Participatory vs. Designer (Conceptual Model)
Participatory
Users are involved in the design of the scenarios.
Designer based scenarios
Designer uses conceptual model to develop scenarios.
Conceptual Model = Mental Model???

3. Scenarios
Scenario Implementation
System Model
System architecture: device + data flow

3. Scenarios: System Model

3. Scenarios
Scenario Implementation
System Model
System architecture: device + data flow
Scenario Cases
Goals, Objects, Actions, Time, etc.

Developing a Conceptual Model
Object and Action Analysis
Lexicon or Ontology
Scenarios
Mental Model = Conceptual Model
Cartoon by Mark Parisi. Used by special permission.

Benefits of Conceptual Model
Identifies actions that are shared by many objects.
Forces the designer to think about the user.
Ontology allows designer to communicate with the users.
Conceptual Model will conform to User’s Mental Model

In Class Exercise
Student Registration Form from Lab#2.
Develop a conceptual model for the registration form.