Methods for Designing Software to Fit Human Needs and Capabilities Proceedings of the Workshop on Software Human Factors (1985) / Chapter Skim
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Human Factors Methods in Research and Product Design
Human Factors Methods in Research and Product Design
Pages 4-17
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From page 4... ...
Both questionnaires and interviews are good methods for eliciting information about how a person goes about his or her work, what aids or tools he or she uses or desires, what kind of knowledge or training is required to do the work, what difficulties he or she reports about the work, where the work originates and where it goes, what interactions are necessary with other people to do the work, and how the user thinks the work process could be improved. Questionnaires are more rigid in format than interviews, since interviews can go where the interviewee leads, often uncovering unanticipated new information.
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From page 5... ...
Data about work can be gathered in detail over a long period of time, especially about how much time particular kinds of activities take and their sequential dependencies. Because a shorter time elapses between the occurrence of an event and its report, diaries give a more accurate record of actual activity than retrospective reports in questionnaires and interviews (Mantel and Haskell, 1983)
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From page 6... ...
The data may be collected by direct observation or by analyzing video or film recordings. Individual samples of categorized activities are aggregated into activity frequency tables, graphs, or state transition diagrams.
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From page 7... ...
Results of task analyses are used not only in writing functional specif ications for a particular application, but also for assigning work to groups of workers, arranging equipment in an efficient configuration, determining task demands on people, and developing operating procedures and training manuals (see Bullen and Bennett, 1983: Bullen et al., 1982)
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From page 8... ...
Thus, they would prescribe appropriate type fonts, but not what words these fonts should express to the user to suggest the appropriate analogy for performing the task on the system. There are several major caveats in the use of design guidelines: the prescriptions or recommendations contained may have been derived from situations or research not applicable to the system being designed; new or unaccounted for variables may interact in unanticipated ways; and current guidelines do not always publish the source of the recommendation, whether it was generated by a controlled laboratory study or derived from the collected wisdom of experience.
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From page 9... ...
For example, theories of color contrast can provide insight into the appropriateness of certain combinations used in screen highlighting or predict the readability of a new monochrome display color. Because Fitt's Law accounted for movement time for placing a cursor in a desired position with a mouse and for placing the appropr late f inger on a desired key location, two conclusions follow: the invention of faster pointing devices was unlikely to increase performance and the design of keyboards with larger per ipheral key caps would increase the accuracy of keying (Card et al., 1978; Card et al., 1980b)
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From page 10... ...
This can be done with the design as specified in a number of different formats, using an experimental simulation of a prototype or even with the experimenter presenting paper and pencil figures of the screens, menus, and commands in the appropriate sequence. The technique helps to identify confusing, unclear, or incomplete instructions, illogical or inefficient operations, unnatural or difficult procedures, and procedural steps that may have been overlooked because they were implicitly rather than explicitly defined.
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From page 11... ...
The hope embodied in this approach is that as the science of user-interface design grows, analytic tools will improve to the point of making the actual user testing of designed systems merely a last, short check of a good, finished design. DESIGN: BUILDING A PROTOTYPE Three methods provide simulations or quick versions of significant aspects of a new system so it can be tried by actual users.
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From page 12... ...
The speed of building a running system depends mainly on the underlying supporting software, which makes the specific prototype programmable from existing modules. Ideally, the prototype programming language separates elements of the dialog from the actual implementation software.
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Experimental Designs Field tests to evaluate systems are fashioned after laboratory tests common in the academic field of experimental psychology. In general, they require the comparison of at least two systems, systems that differ in only one component or variable.
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From page 14... ...
One might, for example, require the user to access item. distant from what is being presented on the current screen or to perform a long command sequence, to determine the loads of this part of the design on the user's ability to imagine the stored information's underlying structure or the mnemonic characteristics and grammatical rules implied by the command sequences.
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From page 15... ...
The amount of time a task takes (either how long an entire task takes or how long each successive keystroke takes) reflects the time it takes the user to perceive inputs, categorize and plan appropriate actions, and execute proper responses.
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One problem with users' reports, however, is that they are typically distorted by their experience with other, similar systems. Or a user may have difficulty separating components of the system sUchs for example, a user who has a very difficult time using a system may report that he or she likes it a great deal, recognizing how much easier it is to perform the task on a computer compared with previous manual methods.
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From page 17... ...
, or a redesign is called for, sending the product design process back to prototype development or fully back to the top of the cycle.
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