paper: designing for usability

My prelims are coming sooner that I'd like to admit, and so I need to get hopping reading a bunch of papers. Fortunately, over the past semester our reading group read over half the assigned papers, but for those that are left I will be posting my summaries here for my own archival purposes (including some back-posts for previously read papers). Perhaps they will be of use to someone else as well, so I might as well make these public...

First up is "Designing for Usability: Key Principles and What Designers Think" by John D. Gould and Clayton Lewis. This paper was originally published in 1985 in the Communications of the ACM, and outlines the iterative design philosophy that is central to modern Human-Computer Interaction. The paper describes three central design principles (early focus on users, empirical measurement, and iterative design) and includes a survey of designers trying to ascertain how common and/or obvious these principles are. The paper also rebuts arguments against the use of these principles and presents a case study of these principles in action.

My biggest problem with this article is that the authors are too unsympathetic to the demands that a deadline-driven project can make. They seem to advocate iterating "as long as it takes", which while desirable is not particularly feasible. To be fair, they acknowledge these pressures and give some cogent arguments for why the costs of iteration are not as high as one might otherwise suspect. But what is missing in the methodology are strategies and techniques for optimizing the design as much as possible within bounded resources. Later work has attempted to address some of these issues, including discount usability methods (e.g., heuristic evaluation) and rapid ethnography techniques (e.g., David Millen's paper).

Designing for Usability: Key Principles and What Designers Think
John D. Gould and Clayton Lewis
Communications of the ACM, March 1985 - Volume 28, Number 3

• The Principles
  • Early Focus on Users and Tasks
    • Understand who the users will be
    • Study cognitive, behavioral, anthropometric, and attitudinal characteristics
    • Study the nature of the work to be accomplished
  • Empirical Measurement
    • User test prototypes on intended users
    • Observe, record, and analyze performance and reactions
  • Iterative Design
    • Cycles of discovering and fixing problems
    • Design, Prototype, Evaluate, Re-Design, ...
• Principles are NOT obvious
  • Survey discovered that most designers at a human factors conference missed most of the principles
    • 62% - Early focus on users
    • 40% - Empirical measurement
    • 20% - Iterative design
• Principles in more detail
  • Early Focus on Users
    • Understanding potential users (as opposed to identifying, describing, etc)
    • Bringing design team into direct contact with potential users
    • Make contact prior to system design
    • Participatory design
      • Have typical users participate in early formulation stages
  • Empirical Measurement
    • Behavioral measurements of learnability and usability
    • Conducting studies very early in the development process
    • Designed not to study a prototype but how people use and react to the prototype
  • Iterative Design
    • A process to ultimately ensure goals are met
• Why the principles are undervalued
  • Not Worth Following
  • Confusion with Similar but Critically Different Ideas
  • Value of Interaction with Users is Misestimated
    • User diversity is underestimated
    • User diversity is overestimated
    • Belief that users do not know what they need
      • A priori vs. knowing it when they see it
    • Belief that my job doesn not require it or need it
  • Competing Approaches
    • Belief in the power of reason
      • Reason alone is likely to miss true work practices and cost structures
    • Belief that design guidelines should be sufficient
      • Guidelines ill-suited for highly context-dependent choices
    • Belief that good design means getting it right the first time
      • Humans unpredictable, necessitating an empirical approach
  • Impractical
    • Belief that the development process will be lengthened
      • Assumptions
        • Usability work must be added to the end of the development cycle
        • Responding to tests must be time consuming
      • Rebuttals
        • User testing can start before a system is built
          • Discount methods - paper prototyping, wizard of oz studies
          • Helps bootstrap project - something tangible to motivate, stimulate thought
        • Modular design, multi-tiered designs - decouple UI from system internals
      • Still has price, but not as high as supposed
      • Poor design brings costs of it's own (support, vendor costs, updates)
    • Belief that iteration is just expensive fine-tuning
      • No, it is a basic design philosophy
    • Belief in the power of technology to succeed
      • From user's perspective, user interface is the product
• Elaboration of Principles
  • Initial Design Phase
    • Preliminary specification of the user interface
    • Collect critical information about users
    • Develop testable behavioral goals
      • Description of intended users (demographic)
      • The tasks to be performed and circumstances of user
      • The measurements of interest
    • Organize the work
      • Software, manuals, etc should be built by the same group
  • Iterative Development Phase
    • Test behavioral goals, continuous evaluation
    • Modification of the interface
    • Fast, flexible prototyping
    • Highly modular implementations
    • Be prepared for results that dictate radical change
    • User comments and think-aloud protocol can help point the way for designing fixes