Quantitative Modeling of Human Performance in Complex, Dynamic Systems (1990) / Chapter Skim
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4. Issues and Research Recommendations
4. Issues and Research Recommendations
Pages 72-86
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From page 72... ...
1. Complex/comprehensive models: Most existing HPMs have been developed only for relatively simple situations.
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From page 73... ...
This Is as true for models in economics and physics as it is in human performance modeling. As such, comprehensive HPMs lack the kind of scientific validation that has been achieved for many simpler models.
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From page 74... ...
· Should the total system modeling effort and the development of comprehensive HPMs simply be abandoned and existing models used as part-task analysis tools? In other words, should "business as usual" prevail, with research efforts aimed at improving existing models or developing single-task models for the new tasks of interest?
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From page 75... ...
With respect to constructing comprehensive HPMs, it is highly unlikely that a single supermodel incorporating all levels of complexity could be developed in the foreseeable future or, for that matter, that it would be a particularly useful tool. A truly universal HEM is almost certain to be too complex to understand and use efficiently.
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From page 76... ...
The problems associated with the parameter~tion of comprehensive HPMs will be substantially more difficult than those for simple, singleprocess models. ~ help understand the difficulties somewhat, note that model parameters generally fall into four classes: 1.
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From page 77... ...
For example, the parameters describing distnbudons for task completion times in task network models may be based on empirical data for the specific task/condition or a related one; they may be predicated on some theoretical basis such as Fitts' law; or they may be various parameters of the describing function models for control tasks which are specified on the basis of verbal adjustment rules that result from theoretical considerations and empirical data.
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From page 78... ...
This scheme may have to be augmented to reflect parameters related specifically to computer implementation of the HEM, such as sample rate and bit size. Research into systematic methods of parameter identification, estimation, and evaluation for complex HPMs is needed.
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From page 79... ...
If so, what are they; if not, can they be developed? As a result of these difficulties, comprehensive HPMs lack extensive scientific validation a compilation of several independent, critically examined studies showing that in a vaneW of human-mach~ne systems the crucial statistics on operator performance are in close agreement with the statistics predicted by a comprehensive HPM.
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From page 80... ...
Underutilization/Inaccessibility of Human Performance Models Issues Considerable use is made of specialized HPMs, which are often constructed for the task at hand. Relatively little use is made of large, comprehensive HPMs except by their developers and groups associated with them.
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From page 81... ...
Recommendations In general, efforts should be made to reduce the costs of comprehensive HPMs and to make available to potential users enough information so that they can make an informed decision conceding model use. When relevant experts, not just the original developers, find a comprehensive HPM to be useful, government agencies should support the development of easily used versions on the most inexpensive machines possible.
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From page 82... ...
This is a nontrivial cost that must be borne to allow for proper evaluation and application by users other than the model developers. Documentation of fundamental assumptions, theoretical bases, and embedded data, as well as software implementations, should be a deliverable in contracts involving the development of a human performance model that is proposed for immediate or near-term application.
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From page 83... ...
Mental Models to Account for Mental Aspects of Tasks Issues Advances in microprocessor and display control technologies have altered the roles of humans in He operation of complex systems. The result Is an increasing emphasis on the cognitive aspects of a task as opposed to its perceptual and psychomotor components.
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From page 84... ...
Unfortunately, the catchall term mental a models, although popular, is not sufficiently well defined and understood to be particularly useful for human performance modeling. There is an underlying assumption that changes In mental models lead to changes in performance.
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From page 85... ...
However, much more effort is recommended if this approach to human performance modeling is to achieve a reasonable level of methodological rigor. Accounting for Individual Differences Issues Humans differ from one another in a number of physical, cognitive, and emotional ways.
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From page 86... ...
This process forces consideration of the assumptions and design decisions which underlie assertions that the system will work with available personnel In all, there are compelling reasons to believe that systematic human performance modeling efforts should be regularly advocated and used along with expert judgment and manned part- and full-task simulation, as a regular part of the design process for large-scale human-machine systems.
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