RUNNING HEAD: COGNITIVE TASK ANALYSIS

 

 

Thinking About Work/Thinking at Work:

Cognitive Task Analysis

 

Rosemarie Reynolds and Michael Brannick

University of South Florida

 

In R. P. Tett & J. C. Hogan  (Co-Chairs), Recent developments in cognitive and personality approaches to job analysis.  Symposium presented at the 17th annual conference of the Society for Industrial and Organizational Psychology, Toronto (April 2002).

 

 

During the writing of this paper, Rosemarie Reynolds was supported as a Graduate Research Fellow by the Naval Air Warfare Center Training Systems Division, Orlando, Florida.  Correspondence concerning this article should be addressed to Rosemarie Reynolds, Business Department, Embry-Riddle Aeronautical University, Daytona Beach, FL 32114.  Electronic mail may be sent via Internet to mbrannic@luna.cas.usf.edu.


Abstract

The purpose of this paper is to discuss the potential usefulness of CTA as an extension of traditional job analysis. In order to do so, we discuss the application of CTA to training, job design, and selection.


Thinking About Work/Thinking at Work: Cognitive Task Analysis

The purpose of this paper is not to provide an exhaustive review or evaluation of  cognitive task analysis (CTA) techniques, but rather to discuss the potential usefulness of CTA as an extension of traditional job analysis that focuses on the knowledge and thought processes supporting observable task performance (Schraagen, Chipman, & Shalin, 2000). As an extension of traditional job analysis, CTA has its roots in the classical time and motion study research of the scientific management school.  In the 1950's, the concept of mental workload, and the notion that information processing, rather than physical effort, determined the time to complete a task, was added to the time and motion study approach.  Other contributions from educational psychology, knowledge engineering, software engineering, and human factors lead to the eventual emergence of CTA in the late 1970s (Annett, 2000).

As with job analysis, the choice of cognitive task analysis methods rests primarily on practicality and purpose (Levine, 1983).  For many jobs, the highly labor intensive process of analyzing cognitive requirements would not provide any value beyond that derived from a standard job analysis.  However, a CTA may be indicated if a task is complex, ill-structured, dynamic, uncertain, and involves decision making or teamwork, as the CTA may provide critical information not provided by the job analysis (Gordon & Gill, 1997; Reynolds & Brannick, 2000, Reynolds & Neville, 2002)).

Thus, the CTA process begins with an initial phase that provides an overview of the organizational needs, the resources available for performing the CTA, and the types of knowledge and skills involved in the job (Ryder, Gott, & Neville, 2000).  The second stage, if indicated, involves the selection of a methodology and data collection.  In the third stage, the focus is on data analysis and the presentation/representation of the information in a useful manner.  Although these tasks have been presented as discrete stages, the process is in fact a reiterative one; the types of information needed in stage three will drive the types of data collected in stage two.

The data collection is one of the most challenging aspects of the CTA process for several reasons: 1) much knowledge is tactic or automatic, 2) knowledge may be difficult to verbalize, and 3) subject matter experts may tend to simplify when conveying their knowledge to a non expert, or simply provide whatever knowledge is accessible (Cooke, 1994).  An exhaustive review of data collection not possible here, but Table 1 shows some of the commonly used methods of knowledge elicitation, based on reviews by Hoffman, Shadbolt, Burton, and Klein (1995), who suggested a typology based on 1) the analysis of familiar tasks, 2) interviews, and 3) contrived techniques, and Cooke (1994), who suggested observations and interviews, process tracing, and conceptual techniques as typological dimensions.  Broadly speaking, however, the type of CTA technique chosen depends on a number of factors, including available resources, expertise, and the type of knowledge being acquired. As McCloskey, Geiwitz, and Kornell (1991) pointed out, some techniques are better suited to elicit declarative knowledge, while others are more effective for procedural knowledge. 

Applications In Industrial Psychology

CTA has been widely used in human factors, instructional design, and human-computer interaction.  Its uses in industrial psychology are less widely known.  In the following sections, we will discuss the application of CTA to training, job design, and selection.

 

Analysis of Familiar Tasks

Contrived Techniques

 

 

 

 

Observations And Interviews

•         Task Analysis

•         Documentation analysis

•         Observation

•         Active Participation

•         Focused Observation

•         Structured Observation

•         Unstructured Interviews

•         Structured Interviews

•         Group interviews

•         Automated Interviewing Tools

 

 

 

Process Tracing

•         Protocol Analysis

•         Verbal Reports

•         Verbal On -Line

•         Verbal Off-Line/Simulated Recall

•         Non-Verbal Reports

•         Decision Analysis

•         Group decision making

 

 

 

 

Conceptual Techniques

 

•         Ranking And Rating

•         Repertory Grid

•         Sorting

•         Constrained processing and limited information problems

•         Event Co-Occurrence/Transition Probabilities

•         Correlations/Covariance

 

Table 1.  Knowledge Elicitation Techniques

 

 


Training

     CTA has an extensive history of use in the instructional design field, however; our review will focus on the use of cognitive task analysis to develop training innovations. Schaafstal, Schraagen, & Van Berlo (2000) performed a series of studies investigating troubleshooting skills in radar systems and computer systems technicians. Using verbal protocols, in which technicians were asked to think aloud, the authors determined that knowledge and theory of the functional system a was not sufficient for effective troubleshooting, but that troubleshooting itself was a learned skill; otherwise,  “working memory overload occurs when students have lost track of where they were in the problem solving process because they encountered unforeseen problems while troubleshooting (p. 78).”

As a result of their analysis, recommendations were made regarding training a generic strategy for troubleshooting that prevents information overload, in addition to system-specific functional models and domain knowledge. The generic strategy consisted of training students to systematically apply the four subcomponents of troubleshooting: problem description, generation of possible causes, testing, and diagnosis. 

Problem description involves identifying and comparing normal and abnormal system behavior. Generating possible causes required the ability to decide, for example, if the problem lies in the power supply, CPU, memory, or peripherals, as well as the ability to determine what level of possible causes are worth investigating, e.g. a computer may have thousands of relays; to examine each relay would be highly ineffective. 

Testing requires the ability to make hypotheses, to choose the right test, to execute the test, to set up conditions for measuring test outcomes, and to compare the results of testing to the hypotheses.  Finally, the troubleshooter must evaluate what needs to be done in order to fix the problem. 

In order to evaluate the new training, one group of subjects took a one-week course incorporating the new training in addition to the regular training course, while another group took only the regular training course. Subsequently, both groups were scored on a theoretical knowledge test, as well as on their ability to solve four unfamiliar systems problems.  There was no difference between the two groups on the test of theoretical knowledge, but the experimental group, which had received training how to systematically THINK about problems, performed significantly better, solving twice as many problems as the control group. 

Task Design

     Neerincx  and Griffioen (1996) used cognitive task analysis to identify cognitive task load for the Netherlands Railways, and to redesign jobs based on the results of the analysis. They based their work on the idea that there are three levels of information processing:1) skill, or routine actions, 2) rule, or problem solving actions based on “if/then” rules, and 3) knowledge, which is the most cognitively demanding, and is used in novel situations.  Based on these three levels of information processing, they suggested the following guidelines for job design:

1. The total number of actions in a period should have an upper and lower limit so that there is sufficient time to carry out these actions

2. The task must call for several levels of information processing. Skill-based actions are barely cognitively demanding; the ideal ratio between rule-and knowledge-based actions in cognitive tasks has an upper and a lower limit

3. There should be no long-term period in which only one sort of skill is performed continuously (e.g. performance may decrease after 10 minutes of continuous vigilance)

4. There should be no momentary overloading; several knowledge-based actions should not have to be performed in rapid succession within a short period of time, and rule- or knowledge-based actions should not have to be performed almost simultaneously (p. 545)

A two-part process was used for the analysis in which a fairly traditional hierarchical task model was followed by a  time-line analysis.  For the hierarchical task analysis, the goal was to obtain an ordered description of the tasks allocated to one person   In the case of railway controllers, the three major tasks were (a) to deal with irregularities, (b) to carry out a work plan, and (c) to inform passengers.  For the time line analysis, a sampling of observations was done at peak periods and off peak periods, at different stations with different trainloads and different task allocations.  In each observation, a single traffic controller was observed and videotaped while performing his tasks and thinking out loud.  Actions were charted and evaluated in terms of the guidelines listed above.

The authors found that at two sites, the controllers were under loaded with regards to Guidelines 1 and 2, while at one site they were overloaded.  With regards to continuous action (Guideline 3), at two sites, continuous action was required almost constantly, while at one site it was required occasionally.  One of the periods of overloading (Guideline 4) also coincided with a number of irregularities, which increased the number of knowledge based actions required, adding to the overload situation.

The final step in their analysis involved redesigning the task so as to meet the guidelines. For one of the sites in which the task load was low, the task could be extended by extending the domain to control part of another railway yard. In the second site, workload was also low, and this task could be extended by adjusting task allocation to include carrying out a work plan and informing passengers.  The third site was overloaded.  Possible solutions included reducing the control area during irregularities and designing a computer support system.

Selection

     The uses of CTA in selection range from the development of ability requirements (Axton, Doverspike, Park, & Barrett, 1997; Enkawa & Salvendy, 1989; Glaser, 1986;  Koubek, Salvendy, & Noland, 1994), to job knowledge testing (DuBois,& Shalin,  1995), and the employment interview (Dougherty, Ebert, & Callender, 1986;  Glaser, Schwarz, & Flanagan, 1958). The development of a selection measure for public safety dispatchers by Hunt and Joslyn (2000) is the focus of this section.

Hunt and Joslyn (2000) pointed out that selection presupposes that the skills required by a job are known.  They began developing their test for public safety dispatchers by having four observers observe operations at a dispatch center, consisting of three eight hour shifts, each staffed by two or three call receivers, two or three police dispatchers, a fire-medical dispatcher, and a shift supervisor.

When a call is received, a call receiver obtains details and enters them, as well as an incident classification and priority, into the computer system, at which point the information is sent to a dispatcher.  The dispatcher reviews the description of the incident, a list of available and assigned police units, and a list of all incidents that have been assigned and are still waiting assignment and their priority.  The dispatcher may change the priority classification.  In addition, the dispatcher receives reports directly from officers in the field regarding new incidents, and the handling of existing incidents, which the dispatcher logs into the computer.  The dispatcher is also responsible for checking on officers periodically after they have been assigned to an incident.

As a result of their observations, the researchers decided that the major tasks were classifying (which involves gathering information so classification can be made, either by questioning the caller, or searching databases) and assigning resources (the ability to prioritize actions).  They also decided that their test should identify people who do well in situations requiring multitasking and decision making under time pressure.

The next stage was an experimental manipulation.  A task was constructed (The Abstract Decision Making  (ADM) Task)  that required allocation of resources based on the classification of incidents in which the attributes used to make the classifications would only be partially revealed to the test taker.  ADM is a computer game, in which points are earned by sorting objects into bins based on size, shape, and color.  The objects are not shown to the game player, however; instead the game player must ask questions about the object until they have enough information to sort it into a bin. ADM was evaluated by comparing performance on ADM with performance on dispatching and air traffic control.  Performance on ADM reliably predicted performance in both simulations.

The next step was to develop a test in which participants participated in a call-receiver simulation.  Scripted actors called in, and the participants gathered information that they entered into a computer screen similar to the one used in actual dispatching.  The length of time it took participants to collect the information and classify the call was recorded, as well as the classification assigned.  The correlation between performance in the call simulation and the ADM task was .53 (p<.05).  Thus, this simple computer game (ADM) appears to be able to identify the skills required for successful performance, without requiring the extensive domain specific knowledge that using the simulations themselves for selection would require; e.g. to select candidates based on a dispatch simulation, candidates would have to know how to do dispatching.

Conclusions

CTA offers an extension to job analysis that can be useful in applications other than the

the traditional ones of  human factors design, instructional design, and human-computer interaction.  We have attempted to demonstrate its potential usefulness in training, job design, and selection. 

However, we would like to offer several cautions regarding unbridled enthusiasm for CTA. The added expense and time required by a CTA analysis is not always helpful; the added expense has to be considered against the increased understanding of mental aspects of job performance (the mental strategies, factual knowledge, and so forth).  The analysis will be fruitful to the degree that understanding the mental process is necessary to solving the problem that initially called for the job analysis.

In addition, there are a large number of techniques of CTA.  Much better guidance about

the circumstances in which each is most appropriate, probably linked to the type of task (e.g., negotiation vs. surgery), the purpose of the analysis (e.g. training vs. selection) and the available resources (e.g., task SME, personnel specialist) is needed.

 

 

 


References

Annett, J. (2000). Theoretical and pragmatic influences on task analysis methods. In J.M. Schraagen, S.F. Chipman, & V.L. Shalin, (Eds.), Cognitive Task Analysis, (pp. 25-40). Mahwah, NJ: Lawrence Erlbaum Associates.

Axton, T. R., Doverspike, D., Park, S.R. and Barrett, G.V. (1997) A model of the information processing and cognitive ability requirements for mechanical troubleshooting. International Journals of Cognitive Ergonomics, 1(3), 245-266.    

Cooke, N.J., (1994). Varieties of knowledge elicitation techniques. International Journal of Human-Computer Studies, 41, 801-849.

Dhaliwal, J.S. & Benbasat, I. (1990). A framework for the comparative evaluation of knowledge acquisition tools and techniques. Knowledge Acquisition, 2, 146-166.

Dougherty, W.T.,  Ebert, R.J., & Callender, J.C., (1986) Policy capturing tin the employment interview. Journal of Applied Psychology, 71(1), 9-15.

DuBois, D. & Shalin, V.L. (2000). Describing job expertise using cognitively-oriented task analysis. In J.M. Schraagen, S.F. Chipman, & V.L. Shalin, (Eds.), Cognitive Task Analysis, (pp. 41-56). Mahwah, NJ: Lawrence Erlbaum Associates.

Enkawa, T., & Salvendy, G. (1989). Underlying dimensions of human problem solving and learning: Implications for personnel selection, training, task design, and expert system. International Journal of Man-Machine Studies, 30(3), 235-254.

Glaser, R. (1986). A cognitive science perspective on selection and classification and on technical training. Advances in Reading/Language Research, 253-268.

Glaser, R., Schwarz, P.A., & Flanagan, J.C. (1958). The contribution of interview and situational performance procedures to the selection of supervisory personnel. Journal of Applied Psychology, 42, 69-73.

Gordon, S.E., and Gill, R.T. (1997). Cognitive Task Analysis. In C. Zsambok and G. Klein (Eds.). Naturalistic Decision Making. (pp. 131-140). Mahwah, NJ: Lawrence Erlbaum Associates.

Hoffman, R.R., Shadbolt, N.R., Burton, A.M., & Klein, G. (1995) Eliciting knowledge from experts: A methodological analysis. Organizational Behavior and Human Decision Processes, 62(2), 129-158.

Hunt, E., & Joslyn, S. (2000). A functional task analysis of time-pressured decision making. In J.M. Schraagen, S.F. Chipman, & V.L. Shalin, (Eds.), Cognitive Task Analysis, (pp. 119-134). Mahwah, NJ: Lawrence Erlbaum Associates.

Koubek, R.J., Salvendy, G., and Noland. S. (1994) The use of protocol analysis for determining ability requirements for personnel selection on a computer-based task. Ergonomics, 37, 1787-1800.

Levine, E.L. (1983) Everything you always wanted to know about job analysis, and more: A primer. Tampa, FL: Edward L. Levine..

McCloskey, B.P., Geiwitz, J., & Kornell , J. (1991) Empirical comparisons of knowledge acquisition techniques. Proceedings of the Human Factors Society, USA, 35, 268-272.

Neerincx, M.A., & Griffioen, E. (1996). Cognitive task analysis: Harmonizing tasks to human capabilities. Ergonomics, 39(4), 543-561.

Reynolds, R.T., & Brannick, M. (2000) Is job analysis doing the job: Extending job analysis with cognitive task analysis, The Industrial Psychologist, 39(1), 63 – 67.

Reynolds, R.T. & Neville, K.  (2002). Job Analysis versus Cognitive Task Analysis of Air Traffic Controllers, Paper presented at the Military Psychology Conference, VA.

Ryder, J.M., Gott, S., & Neville, K.J., (2000). Using Cognitive Task Analysis for Instructional Design. Orlando, FL: Naval Air Warfare Center Training Systems Division. (Technical Report 000322.9914)

Schaafstal, A., Schraagen, J.M., & Van Berlo, M. (2000). Cognitive task analysis and innovation of training: The case of structured troubleshooting. Human Factors, 42(1), 75-86.

Schraagen, J.M., Chipman, S.F., & Shalin, V.L. (2000) Introduction to Cognitive Task Analysis. In J.M. Schraagen, S.F. Chipman, & V.L. Shalin, (Eds.), Cognitive Task Analysis, (pp. 3-23). Mahwah, NJ: Lawrence Erlbaum Associates.


Appendix 1: Bibliography of Knowledge Elicitation Resources

Agarwal, R. & Tanniru, M. R. (1991). Knowledge extraction using content analysis. Knowledge Acquisition, 3, 421- 441.

Bainbridge. L. (1990). Verbal protocol analysis. In J. R. Wilson & E. N. Corlett, (Eds.) Evaluation of Human Work: A Practical Ergonomics Methodology, (pp. 161-179). London: Taylor & Francis.

Boose, J. H. (1990). Uses of repertory grid-centered knowledge acquisition tools for knowledge-based systems. In J. Boose & B. Gaines (Eds.), The Foundations Of Knowledge Acquisition: Knowledge- Based Systems, Vol. 4, (pp.61- 84). San Diego, CA: Academic Press.

Boose, J. H. (1989). A survey of knowledge acquisition techniques and tools. Knowledge Acquisition, 1, 3-37.

Brenner, M., Brown, J. & Canter, D. (1985). The Research Interview: Uses and Approaches. London: Academic Press.

Burton, A. M., Shadbolt, N. R., Hedgecock, A. P, & Rugg, G. (1987). A formal evaluation of knowledge elicitation techniques for expert systems: Domain 1. Proceedings of the First European Workshop on Knowledge Acquisition far Knowledge-Based Systems, Reading University, D 3.1- D 3.20.

Burton, A. M., Shadbolt, N. R., Rugg, G. , & Hedgecock, A. P. (1990). The efficacy of  knowledge elicitation techniques: A comparison across domains and levels of expertise.  Journal of Knowledge Acquisition, 2, 167-178.

Cooke,  N. J. (1994) Varieties of knowledge elicitation techniques. International Journal of Human-Computer Studies, 41, 801- 849.

Corter, J.E. & Tversky, A. (1986) Extended similarity trees. Psychometrika, 51, 429-451.

Dhaliwal, J.S. & Benbasat, I (1990). A framework for the comparative evaluation of knowledge acquisition tools and techniques. Knowledge Acquisition, 2, 146-166.

Flanagan, J.C. (1954) The critical incident technique. Psychological Bulletin, 51, 327-358.

Geiwitz, J., Klatzky, R.L., & McCloskey, B.P. (1988). Knowledge acquisition techniques for expert systems: Conceptual and empirical comparisons. Santa Barbara, CA: Anacapa Sciences.

Geiwitz, J., Kornell, J., & McCloskey, B.P. (1990). An expert system for the selection of knowledge acquisition techniques. Santa Barbara, CA: Anacapa Sciences. (Technical Report 785-2).

Gordon, S. E. & Gill, R. T. (1989). Question probes: A structured method for eliciting declarative knowledge. AI Applications In Resource Management, 3, 13-20.

Grabowski, M., Massey, A. P. &. Wallace. W. A. (1992). Focus groups as a group knowledge acquisition technique. Knowledge Acquisition, 4, 407-425.

Grover, M.D.(1983). A pragmatic knowledge acquisition methodology. Proceedings from the International Joint Conference on Al, West Germany, 436-438.

Henrion, M. & Cooley, D. R. (1987). An experimental comparison of knowledge engineering for expert systems and for decision analysis. Proceedings of the Sixth National Conference on Artificial Intelligence, Seattle, 471-476.

Hoffman, R.R., Shadbolt, N.R., Burton, A.M., & Klein, G. (1995) Eliciting knowledge from experts: A methodological analysis. Organizational Behavior and Human Decision Processes, 62(2), 129-140.

Kitto, C. M. & Boose, J.  (1989). Selecting knowledge acquisition tools and strategies based on application characteristics. International Journal Of Man-Machine Studies, 31, 149-160.

Klein, G. A., Calderwood, R. &- Macgrecor, D. (1989). Critical decision method for eliciting knowledge. IEEE Transactions On Systems, Man, & Cybernetics, 19, 462-472.

Krippendorff, K. (1980). Content analysis: An introduction to its methodology. Beverly Hills, Ca.:Sage.

Krumhansl, C. L. (1978). Concerning the applicability of geometric models to similarity data: The interrelationship between similarity and spatial density. Psychological Review, 85,115-129.

Kruskal, J. B. (1977). Multidimensional scaling and other methods for discovering structure. In K. Enslein, A. Ralston, & H. S. Wilf, Eds. Statistical Methods For Digital Computers. New York: Wiley.

Littmann, D.C. (1986). Modeling human expertise in knowledge engineering: Some preliminary observations. Proceedings of the First Knowledge Acquisition for Knowledge-Bases Systems Workshop, Banff, 28.

McCloskey, B.P. Geiwitz, J.  and Kornell , J. (1991) Empirical comparisons of Knowledge acquisition techniques. Proceedings of the Human Factors Society, 268 – 272.

McGraw, K.L. & Harbison-Briggs, K. (1989) Knowledge Acquisition: Principles and guidelines. Englewood Cliffs, NJ: Prentice Hall.

Michalski, R.S. & Chilausky, R.L. (1980). Learning by being told and learning from examples: An experimental comparison of the two methods of knowledge acquisition in  the context of developing an expert system for soybean disease diagnosis. Policy Analysis and Information systems, 4.

Miles, D.E., Hoffman, K.A., Foster, L.L., King, T., Gordon, T., Riddle, D., Coovert, M., Elliott, L.R.,  & Schiflett, S.  (2000).  A qualitative methodology for integrating cognitive task analyses data. Poster presented at the 15th Annual Conference of the Society for Industrial and Organizational Psychology, New Orleans, LA, 2000.

Morik, K. (1991). Underlying assumptions of knowledge acquisition and machine learning. Knowledge Acquisition, 3,137-156.

Mostyn, B. (1985). The content analysis of qualitative research data: A dynamic approach. In M. Brenner, J. Brown & D. Canter, Eds. The Research Interview: Uses And Approaches. (pp. 115-145). London: Academic Press.

Olson, J. R. & Rueter, H. (1987). Extracting expertise from experts: Methods for knowledge acquisition. Expert Systems, 4, 152-168.

Reitman, J. S. & Rueter, H. (1980). Organization revealed by recall orders and confirmed by pauses. Cognitive Psychology,  554-581.

Reynolds, R.T. & Neville, K.  (2002). Job Analysis versus Cognitive Task Analysis of Air Traffic Controllers, Paper presented at the Military Psychology Conference, VA.

Russo, J. T. &, Rosen, L D. (1975). An eye fixation analysis of multialternative choice. Memory And Cognition, 3, 267-276.

Scherer, K. R. & Ekman, P. (1982). Handbook of methods in nonverbal behavior research. Cambridge: Cambridge University Press.

Schraagen, J.M., Chipman, S.F., & Shalin, V.L. (2000) Introduction to Cognitive Task Analysis. In J.M. Schraagen, S.F. Chipman, & V.L. Shalin, (Eds.), Cognitive Task Analysis, (pp. 3-23). Mahwah, NJ: Lawrence Erlbaum Associates.

Schvaneveldt, R. W., Durso, F. T., Goldsmith, T. E., Breen, T. J., Cooke, N., Tucker, R.G. & DeMaio, J.C. (1985). Measuring the structure of expertise. International Journal Of Man-Machine Studies, 23, 699-728.

Scott, A. A., Clayton, J. E. & Gibson, E. L (1991). A practical guide to knowledge  acquisition. Reading, Ma: Addison-Wesley.

Shaw, M. L. & Woodward, J.B.(1988). Validation in a knowledge support system: Replication and consistency with multiple experts. International Journal of Man-Machine Studies, 29, 329-350.

Smith, J. B., Smith, D. K. & Kupstas, E. (1993). Automated protocol analysis. Human Computer Interaction, 89, 101-145.

Sowa, J. F. (1992). Conceptual analysis as a basis for knowledge acquisition. In R. R. Hoffman, Ed. The Psychology Of Expertise: Cognitive Research And Empirical Al, (pp. 80-96). New York: Springer-Verlag.

Thordsen, M.L. (1991). A comparison of two tools for cognitive task analysis: Concept mapping and the critical decision method. Proceedings Of The Human Factors Society,. 283-285.

Welbank, M. (1990). An overview of knowledge acquisition methods. Interacting With Computers, 2, 83-91.

Woodward, B. (1990). Knowledge acquisition at the front end: Defining the domain. Knowledge Acquisition, 2, 73-94.

Wright, G. & Bolger, F., Eds. (1992). Expertise And Decision Support. New York: Plenum Press.