The Life Cycle of Interface Design

1
The Life Cycle of Interface Design

• HI 6001 Healthcare Interface Design
• Week 4

2
Steps in Interface Design

• Various Analyses
• User Analysis
• Task Analysis
• Functional Analysis (e.g., cognitive work
  analysis)
• Comparative Analysis (e.g., representational
  analysis)
• Environmental Analysis
• Usability Goal Analysis
• Financial Impact Analysis
• Design Options
• Parallel Design
• Participatory Design
• Guidelines and heuristics
• Prototyping
• Evaluation
• Iteration
• Feedback

3
User Analysis

• Different Users - Horizontal Dimension
• Installers
• Maintainers
• System administrators
• Other support staff
• Users who prepare input for the system
• Users who use the end product or output of the
  system
• Different Users Vertical Dimension
• Beginner
• Novice
• Intermediate
• Expert

4
User Analysis

• Users Individual Characteristics
• Work experience
• Educational level
• Age (e.g., children, seniors, etc.)
• Previous computer experience
• Cultural background
• Personality
• Time available for learning or training
• Frequency of use
• Example Non-textual interface for very young
  children

5
User Analysis

• How to do user analysis
• Market analysis
• Site visit
• Observational studies
• Questionnaires
• Interviews
• Participation

6
Task Analysis - Approach

• Users goals
• How users currently approach the task
• Information needs
• How to deal with exceptional circumstances
• Input and out needs (obtained by users talking to
  clients
• Users model of tasks (e.g., metaphor)
• Weaknesses of current system (fail to achieve
  goals, spend excessive time or are made
  uncomfortable)

7
Task Analysis - Outcomes

• System functions that have to be achieved
• Procedures and actions to be carried out to
  achieve task goals and interdependencies of the
  procedures
• Information to be processed
• Input and output formats that are required
• Constraints that must be considered.
• Communication needs for information exchange.
• Organization and structure of the task

8
Functional Analysis

• Identify the optimal task structure
• Example Cognitive work analysis
• Current task structure may be only sub-optimal
• Paper-based patient records
• New functions and features afforded by new
  technology
• Technology change tasks
• Example should online courses mimic face-to-face
  communication or do they provide new features
  that enhance learning?
• Example EMR vs. paper-based patient records

9
Comparative Analysis

• Functionally equivalent products
• Existing and competing products are best
  prototypes of own planned products
• Representational analysis
• Representations are the most important feature of
  interface design.
• Isomorphic representations have different
  representational efficiencies, task difficulties,
  and behavioral outcomes
• Should be associated with functional analysis
• Different implementations of the optimal task
  structure obtained from functional analysis

10
Environmental Analysis

• Physical environment
• Sensory context lighting (affect screen design)
  noise (affect auditory design)
• Settings home, ICU, ward, office, warehouse,
  mobile, classroom, shopping mall, etc.
• Room sharing e.g., audible alarms are not
  appropriate for cubicle workers
• Constraints network speed, computer speed
• Social, Spatial, and Temporal Environment
• Multiple users or single users
• Same place or different places
• Asynchronous or synchronous
• Multiple users

11
Usability Goal Analysis

• Ease of use
• Ease of learning
• Subjective satisfaction
• Flexibility
• Customizability
• Human errors
• Information seeking, gathering, retrieval,
  manipulation

12
Financial Impact Analysis

• Phone 0.15 seconds/digit ? 1,000,000/year
• 757 3 pilots ? 2 pilots
• Pager 3000 words ? 150 words
• Form 100,000 total ? 536,023/year
• Sign-on 20,700 total ? 41,700 1st day
• IBM 1 investment ? 100 return

13
Financial Impact Analysis

• 1993 survey of 31 projects
• Project size in person-year 23
• Actual budget over total 6
• Actual usability effort in person-year 1.5
• Ideal usability effort in person-year 2.3

14
Parallel Design

• Several independent designers or teams to
  generate different designs
• Up to preliminary designs
• Or up to final products
• Explore design space
• Diversified parallel design
• Not for entire product, but for components of a
  product
• Example one for novice and one for expert

15
Participatory Design

• Designers are not users.
• Users should participate in the design.
• However, users are not designers.

16
Guidelines and Heuristics

• General guidelines
• Specific guidelines
• Heuristics
• Example Shneidermans eight golden rules
• Strive for consistency
• Enable frequent users to use shortcuts
• Offer informative feedback
• Design dialogs to yield closure
• Offer error prevention and simple error handling
• Permit easy reversal of actions
• Support internal locus of control
• Reduce short-term memory load

17
Prototyping
18
Evaluation

• Expert Review
• Survey
• Cognitive walkthrough
• Ethnographic observation
• Empirical testing
• Thinking aloud (audio and video)
• Controlled experiments
• Log files

19
Iteration

• Iteration is the rule, not exception.
• Iterations way temporarily make some features
  worse.

20
Feedback

• Feedback from field use
• Product upgrades