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Chapter 4 : Descriptive Approaches

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Title: Chapter 4 : Descriptive Approaches


1
Chapter 4 Descriptive ApproachesWhat workers
really do
  • ? ? ?

2
Contents
  1. Purpose
  2. Descriptive approaches Current practice
  3. Why descriptive approaches are not enough?
  4. Existing techniques for getting around the
    task-artifact cycle
  5. An alternative way of getting around the
    task-artifact cycle

3
Purpose
  • Using Four cases
  • To illustrate the important contributions of
    descriptive approaches
  • To identify additional dimensions that must be
    considered in work analysis
  • Descriptive approach
  • One of possible means to investigate intrinsic
    work constraint, rather than an end itself
  • Computer-based information systems should not be
    designed based solely on studies of currents. ?
    Formative Approach

4
Scope of descriptive approaches
  • Descriptive WA is accomplished by conducting
    field studies that
  • document the practical challenges that workers
    actually face on the job
  • and the practices that workers have developed to
    cope with those challenges
  • Europe VS America
  • 30 years tradition in Europe
  • Task VS Activity
  • Task Official actions that are prescribed to
    workers. (Normative approach)
  • Activity Informal actions that workers actually
    perform in practice (Descriptive Approach)
  • There are many different perspectives in
    descriptive approaches ? 4 categories
  • A case study from situated action
  • A case study from naturalistic decision making
  • A case study from activity theory
  • A case study from distributed cognition

5
A case study from situated action
  • Suchman (1987)
  • Anthropologist
  • ? ?? ????? phototype ?????? ????? photocopying
    machine? ??? ? ??? ???? interact??? ??
  • Conversation ??
  • ??? ??? ??? ??? ?? ??? ??? ???? ??
  • Theoretical Foil
  • Artificial intelligence approach to planning
  • The same perspective to the instruction based
    approach

6
Suchman(1987) ? ??
  • An instruction-based approach is constrained by
    limitation on the designers ability to predict
    any users action
  • ????? ?????? ???? ???? ???? ?? ???? ?? ??? ??.
  • ??? ????? ??????? ???? ?? ??? ???? ???.
  • Suchman said that purposeful actions are
    inevitably situated actions
  • Situated actions are responding to local
    interactions contingent on the actors particular
    circumstances
  • ?? Actual behavior is far from the rational
    ideal

7
A case study from naturalistic decision making
  • Klein(1989)
  • Experimental Psychologist
  • ????? ??? ??? ????? ???? ?? ???? ??????? ?? ??
  • Retrospective naturalistic studies
  • ?? 23?? ? ?????? ???? ????? ?? ???? ????? ??
  • Theoretical Foil
  • Classical decision making To follow a thorough
    and rational approach
  • ?? ? ??????, ? ??? ??? ??, ??? ??

8
Klein(1989) ? ??
  • ??? ??? ?? ??? ???? ??? ??
  • Why experts go with the flow
  • ????? ??? ?? ??? ??? ??? ? ?? ??? ?? Too
    laborious mental deliberations.
  • Not to find optimal action, but to find
    satisfactory action (feasible, timely and
    cost-effective)
  • ????? ????? ???, ?? ?? informative cues ? ??? ?
    ?? ????? ???. Action? ??? ??? ?? ??
  • ?? ?? informative cues ? ??? ? ??, ? Cue?? ??
    ????? ????? ????? ??? ? ??. ??? ???? ??? ?? ????.
  • ??? ??? ? ?? ???, ??? ??? ??? ??? ??? action?
    ???? ??.
  • ??? ???? ??? ?? ??? ??? ??? ??? ?? ??? action?
    ??.

9
Klein(1989) ? ??
  • Recognition-Primed Decision-making (RPD)
  • ?????? ??? ????, ????? ????? ???? ???
    ??(recognize)? ? ??.
  • ??? situation assessment? ?? ???? ?? ???.
  • ?? Actual decision making is far from the
    normative approach prescribed by classic decision
    theory

10
A case study from activity theory
  • Bødker(1991)
  • Computer scientist
  • The participatory design of computerbased
    systems
  • UTOPIA Project
  • ????? ??? ??? ?????? ???? ?? Descriptive task
    analysis? ?????.
  • ??????? ?? ?? ?? ??, ????? ?? ? ??
  • ? ???? ??? ??
  • Theoretical Foil
  • Anglo-American approach to HCI

11
Bødker(1991) ? ??
Activity theory-based HCI Anglo-American HCI
Context-based Context-based Little Context-based
Semantic/ Syntactic semantic features of the interface Syntactic and Lexical features of the interface
Usefulness/ Usability Usefulness (functionality) Usability
Perspective Ecological perspective Cognitive perspective
  • She wanted to find a systematic framework
  • Thus, to adopt activity theory originated from
    the psychology of Soviet union

12
Bødker(1991) ? ??
  • Activity theory could be adapted to the practical
    needs of HCI and its concepts provided a good
    descriptive understanding of the idea collected
    during UTOPIA
  • Activity theory is the study of goal-directed
    activity
  • Instead of focusing on the device, goal-focus
  • Goal focus? ??
  • ???? semantic? ?? ?? ??? ???
  • Goal-oriented activity? ??, ??? context??? ??? ??
    ????.
  • Goal-oriented activity? ??? ??? ???? ???? ??,
    ???? ??? ???? ??? ???.
  • ?????, context-conditioned variability

13
A case study from distributed cognition
  • Hutchins (1995)
  • Anthropologist
  • Field study of current practice in the domain of
    ship navigation
  • On the navigation bridge of a number of US Navy
    ships at sea
  • To understand the nature of human cognition in
    naturalistic settings
  • Theoretical Foil
  • Physical symbol system hypothesis (PSSH)
  • Such as digital computer, human cognition
    involves mental information processing driven by
    well-defined rules and representations stored in
    human memory.

14
Hutchins(1995) ? ??
  1. Information processing are not confined to the
    brain, but are instead distributed spatially
    across individuals and artifacts and temporally
    as a function of the history of a particular
    culture.
  2. Workers frequently accomplished task goals, not
    in isolation through mental information
    processing, but as a functional team through
    mutual coordination of their actions
  3. Cognition in the wild is an emergent activity
    that is not completely specified ahead of time.
  4. Historical influence of cultures were very
    important. Many useful artifacts and many of the
    practices were adapted products of navigational
    experience. ? Not a strict mental activity
    mechanically performed by an individual.

15
Comparison of four case studies
?? ???? ?? ???? ?? ?? ?? ??
Suchman (1987) Anthropology Photocopying Artificial Intelligence Situated Action
Klein (1989) Experimental Psychology Fire Fighting Classical decision making RPD Model
Bødker (1991) Computer Science Graphic Design Anglo-American HCI Activity theory-based HCI
Hutchins (1995) Anthropology Ship Navigation Physical symbol system Hypothesis Distributed Cognition
???? Simonsen and Kensing (1997), Suchman (1995)
16
Importance of current practice
  • 4?? ??? ???
  • ?? ??? ?? ????? ?? ??
  • ?? ????(??)
  • Theoretical foil ? ??
  • 4?? ??? ???
  • It is the enormous value of conducting
    descriptive studies of work in representative or
    naturalistic settings
  • Converging characterization of human work
  • Context-conditioned variability? ???
  • Human work? strong social components? ???.
  • Work is also seldom solely focused on internal
    mental processing because worker create tools
    reducing the burden on scare cognitive resources.
  • Current work practices are shaped by historic
    cultural factors.
  • Time pressure and other constraint??? ??? ???,
    ??? ?? ????? ??? ????? ???.

17
Implications for work analysis
  • Work analysis framework must include at least
    five dimensions of work
  • Work domain analysis ??
  • ???? ?? ??? ??? ?? information requirements? ????
    ??
  • Constraint-based task analysis ??
  • ????? flexible, situated manner? ????? ??? ??
    information requirements? ???? ??
  • Effective Strategies? ?? ??
  • ?? ????? ???? ?? ??? ?? ??? ? ?? ????? ???? ??
  • Social and organizational factors? ??? ??
  • Computer based information system? ???? ?? ???
    ????? ??? ? ? ????, ?? ??, ????? ?? ?
  • ???? ??? Workers competences(??,??) ??
  • ??? ??? ????, skill acquisition? ???? ?????? ????
    ??

18
Why descriptive approaches are notenough The
task-artifact cycle
  1. Limitations of basing design solely on current
    practice
  2. Are these limitations recognized?
  3. From descriptive analysis to design implications
    The track record
  4. People are adaptive the task-artifact cycle
  5. Summary

19
Limitations of basing design solely on current
practice
  • Intrinsic Work Constraints
  • Constraints on achieving work goals, independent
    of any particular device
  • These constraints are an inherent part of work in
    a particular domain
  • IWC delimit the actions that are required to get
    the job done
  • Current Work Practices
  • Current practice is device-dependent

20
Why computer-based information systems should not
be designed to support current practices.
21
Direction of computer-based information systems
design
  • Currently unexplored actions may require too much
    time, computational effort, memory demands or
    knowledge with the existing device.
  • Then if with the existing information systems,
    workers may simply decides to omit this tasks
  • If the requisite computer support were provided,
    these unexplored possibilities could very well
    become a productive part of workers practices

22
Implications
  • Computer-based information systems should ideally
    be designed to support intrinsic work
    constraints, not just current work practices
  • Two reasons
  • We do not want to base our design on the
    workaround activities that are vestiges of poor
    device design
  • We want to support currently unexplored
    possibilities.
  • Work analysis? ? ????? intrinsic work
    constraints? ???? ???. ??? ??? descriptive
    studies? ???? ??? ?? ?? ???.
  • The point is that future designs should go beyond
    current practice by removing unwanted
    inefficiencies and by adding new functional
    possibilities.

23
Are these limitations recognized?
  • Limitations of Descriptive Analysis
  • Benyon (1992) Embodying current practice in
    future systems is a fundamental error
  • Beyer and Holtzblatt(1998), Holmqvist(1991)
  • However,
  • The analysis of current practices should be
    viewed as one of several possible means to
    investigate work constraints, rather than an end
    in itself

24
From descriptive analysis to design implications
The track record
  • Social science
  • ? ?? ???? ?????, ??? ?? ??? ???? ???
  • Activity theory
  • The descriptive nature of activity theory make it
    difficult to develop a novel design
  • Francophone ergonomics community
  • Human factors community

25
People are adaptive the task-artifact cycle
  • Task-artifact cycle (Carroll et al. 1991)
  • ?? work practice? ???? requirements? ?????
    artifact? ?????.
  • ??? ???? ??? work practice? ?????.

26
People are adaptive the task-artifact cycle
  • If we conduct a descriptive work analysis to
    understand workers current tasks, we will
    identify requirements that could be used to
    design a new artifact

27
Existing techniques for getting around the
task-artifact cycle
  • Rapid prototyping and iterative user testing
  • To create prototypes of new designs and evaluate
    them by having workers use them
  • The end goal is to iteratively maximize the
    overlap between the two sets
  • The subset of workaround activities becomes
    smaller and smaller
  • The subset of currently unexplored possibilities
    becomes smaller and smaller
  • Scenario-based design (Carroll et al. 1991)
  • Analytical techniques for trying to achieve the
    same objective ? Empirical way
  • Scenarios provide a means for analytically
    evaluating Simulated future work

28
Limitations The problems of device-dependence
and incompleteness
  • Strong device dependence
  • A dog chases its tail continuous iteration
    process
  • Incompleteness
  • Scenarios representation is incomplete the
    number and range of tasks
  • Limitation by the ingenuity and creativity of the
    designer
  • EX) Accident data

29
An alternative way of getting around the
task-artifact cycle Modeling intrinsic work
constraints
  • Completeness The need for models

Scenario/Prototype Modeling
Inductive, bottom-up activities Top-down basis for generalization
Dont know what factors are included and what factors are missed To make explicit what attribute have been included
Representing exemplars Representing classes
Models provides a more systematic and explicit
basis for work analysis
30
Device-independence focusing on intrinsic work
constraints (1)
  • Model what?
  • There are many different entities that could be
    modeled
  • To find a way escaping from the regress by the
    task-artifact cycle
  • To find the set of intrinsic work constraints ?
    Not including workaround activities

31
Device-independence focusing on intrinsic work
constraints (2)
  • Work analysis methods should not prespecify the
    follows
  • Existing set of sensors
  • Contents and structure of the database
  • Functionality of the automation
  • Allocation of functions between computer and
    workers
  • Allocations of job responsibilities
  • Appearance and structure of the interface
  • Workers competences
  • Because each issues is a point of design leverage
    ? inheriting the vestiges of the old

32
Device-independence focusing on intrinsic work
constraints
  • The following decisions should be made based on
    the findings obtained from the work analysis
  • What information should be gathered
  • How it should be organized
  • How to automated
  • What to automated
  • How to organize work
  • How to display information
  • How to train operators
  • Ways of identifying intrinsic work constraints
  • Studying the structure of the work domain
    identify efficient tasks and novel strategies
  • Analytical model (e.g. Operation research)
  • Current practice

33
Summary
  • What type of work analysis is appropriate for
    complex sociotechnical systems?
  • Normative approaches
  • Strong limitation
  • Descriptive approaches
  • Limitation
  • Task-artifact cycle inherit the deficiencies of
    current practice
  • To overcome the cycle, prototyping and scenario
    method
  • These limitations can be directly addressed by
    explicitly modeling intrinsic work constraints
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