1. HTA as a framework for task analysis Presenter: Hilary Ince, University of Idaho

2. Introduction Hierarchical Task Analysis (HTA): “explores tasks through a hierarchy of goals indicating what a person is expected to do, and plans indicating the conditions when subordinate goals should be carried out” Not often used for cognitive tasks, paper aims to change that

3. Introduction There is lack of agreement on nature and purpose of task analysis “Task” can be human behavior, system goals, how context constrains goal attainment, or a mix of these “Task analysis” can be an investigatory tool or a method to model human behavior, can be specific and rigorous or just a guideline

4. Introduction Miller’s definition of task: “a group of discriminations, decisions, and effector activities related to each other by temporal proximity, immediate purpose, and a common man-machine output” Not a great definition… temporal proximity is not always there, nor is immediate purpose For this paper, task is a “problem facing an operator” (distinguishes from behavior)

5. Justification of HTA Hierarchy can exert control, where higher levels control lower ones Can also be descriptive, describing sub-goals in relation to each other in terms of their purpose HTA “relates to the strategy of examining a task within a practical project”

7. Strategy in Task Analysis Box 1 – Setting Goals: Begin by identifying main goal associated with the problem Box 2 – Observing Constraints: Goals will have constraints to their attainment… recognize these Box 3 – Calculating criticality: Only examine task elements deemed critical, either subjectively or with data

9. Strategy in Task Analysis Box 4 – Ceasing Rediscription: If current performance is acceptable, do not examine the goal further Box 5 – Generating Hypotheses: If current performance is not acceptable, look for a cause of the problem by examining operator-system interaction Box 6 – Cost-benefit analysis: Do the benefits outweigh the cost of the hypothesis?

11. Strategy in Task Analysis Box 7 – Recording the analysis: If an acceptable hypothesis is selected, show progress, hypotheses proposed, and hypotheses rejected for cost (the cost may prove worth it later) Box 8 – Redescription: If an acceptable hypothesis hasn’t been selected, attempt to redescribe the goal

12. Strategy in Task Analysis Box 9 – Challenging the contraints: If still unable to establish a hypothesis, challenge contraints. Management may allow higher costs, requirements may be able to shift

13. Analyzing Cognition within the Task Analysis Context Article suggests that instead of distinguishing between cognitive and non-cognitive TAs, should consider how general TA accommodates cognitive tasks HTA is deliberately flexible, and can be used in many situations “Task must first be understood to anticipate the demands placed on cognition”

14. Conclusions Task is complementary, not synonymous, with behavior HTA is a general task analysis strategy, not a method for modeling behavior

15. Cognitive task analyses for decision centered design and training Presenter: Hilary Ince, University of Idaho

16. Introduction Cognitive task analysis (CTA): “an approach that ‘determines the mental processes and skills required to perform a task at high proficiency levels and the changes that occur as skills develop’” Critical decision method (CDM): “a retrospective interview strategy that applies a set of cognitive probes to actual nonroutine incidents that required expert judgment or decision making”

17. Method CDM explores actual non-routine events, and what decisions were made Participants asked to recall such a case, and tell the story in detail Cognitive probes used to get participants to think about their situational awareness and planning at the time of the event

18. Study 1 17 whitewater rafting guides with varying experience interviewed Asked to describe an incident when they had to make quick decisions Timelines were created of each event, then summarized into situation assessment records (SAR) A SAR is a breakdown of primary environmental cues, expectancies generated from cues, goals of the guides, and selected course of action

19. Study 1 Results and Discussion 17 critical incidents collected, 52 total decision points 88% of decisions made under 5 seconds As expected, expert guides made decisions based on previous experiences Results showed that mental simulation of the river ahead is helpful, could be a good training tool

21. Study 2 10 experienced GA pilots, average of 10,000 hours experience Asked to recall a situation where an unusual or difficult situation was made regarding weather Probed two weather situations: slowly deteriorating and thunderstorms

22. Study 2 Results and Discussion High degree of consistency between experts regarding critical cues Novices should be trained to recognize these cues Can be taught to apply knowledge through training

24. Study 3 Aim of the study was to determine requirements for a computer system to replace manual ambulance dispatch system 5 dispatchers with 5-9 years of experience interviewed Asked to describe a particularly unusual or difficult situation Details randomly arranged on Post-its, then participants rearranged the details in order Often remembered additional information

25. Study 3 Results and Discussion Interviews coded as cues, situation assessments, goals, and courses of action Goals were identified as: Obtain early, accurate picture of incident Maintain situational awareness Match available resources to needs of situation Get help on the way within three minutes Maintain record of events

26. Study 3 Design Implications Display shows available ambulances near event Supports planning for major incidents

28. Evaluation of CDM Key feature of CDM is use of probes Recreation of the timeline using Post-its was helpful Results of CDM can be used to influence training programs, as shown in these Studies 1 and 2

29. Questions?