An Introduction to Human Factors Engineering by Christopher D. Wickens, Sallie E. Gordon, & Yili liu , pages, $ New York: Longman ISBN. (Introduction to Human Factors Engineering) - Ebook download as PDF File .pdf) , Text File .txt) or read book online. Christopher D. Wickens, John Lee, Yili D. Introduction to Human Factors Engineering Christopher D. Wickens, John ISBN : Author: Christopher D. Wickens, John D. Lee.
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An introduction to human factors engineering I Christopher D. Wickens, Sallie E. Gordon, Yili Liund ed. lesforgesdessalles.info Includes bibliographical references and index. PDF | On Jan 1, , C. D. Wickens and others published An Introduction to Human Factors Engineering. Designing for People: An introduction to human factors engineering. Book · August Christopher D Wickens at Alion Science and Technology.
Successfully reported this slideshow. John D. Some types of benefits are more common for one type of manufacturer or customer than another. For example, the lower-back injury in our leading scenario might have been caused by asking a worker who had neither the necessary physical strength nor the body proportion to lift the component in a safe manner. Eye movements can generally be divided into two major classes. If this is the only discriminating feature between lines.
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View 1 comment. Jan 13, Kc Fellger rated it really liked it. Bruno Mariani rated it really liked it Jan 21, Jenni Ross rated it it was amazing Jan 28, A K rated it did not like it May 01, Tim Holyoake rated it liked it Mar 27, Joren rated it liked it May 19, Rahul Shah rated it liked it Aug 31, Richard Lee rated it really liked it Jan 23, Evan J See rated it liked it Jun 29, He filed a lawsuit against the company for requiring physical action that endangered the lower back.
Examining a bottle of prescription medicine, an elderly woman was unable to read the tiny print of the dosage instructions or even the red-printed safety warning beneath it. Ironically, a second difficulty prevented her from potentially encounter- ing harm caused by the first difficulty. After impa- tiently listering to a long menu of options, she accidentally pressed the number of the wrong option and now has no clue as to how to get back to the option she wanted, other than to hang up and repeat the lengthy process.
While the three episodes described in the introduction are generic in nature and repeated in many forms across the world, a fourth, which occurred in the Per- sian Gulf in , was quite specific. Navy cruiser, was on patrol in the volatile, conflict-ridden Persian Gulf when it received ambigu- ous information regarding an approaching aircraft.
Characteristics of the radar system displays on board made it difficult for the crew to determine whether it was climbing or descending. Incorrectly diagnosing that the aircraft was de-. Christopher D. Tragically, the aircraft was actually an Iranian passenger air- line, which had been climbing rather than descending.
These four episodes illustrate the role of human factors. In these cases human factors are graphically illustrated by breakdowns in the interactions be- tween humans and the systems with which they work. It is more often the case that the interaction between the human and the system work well, often exceed- ingly so.
However, it is characteristic of human nature that we notice when things go wrong more readily than when things go right. Furthermore, it is the situation when things go wrong that triggers the call for diagnosis and solution, and understanding these situations represents the key contributions of human factors to system design.
Human factors involves the study of factors and development of tools that facil- itate the achievement of these goals. We will see how the goals of productivity and error reduction are translated into the concept of usability, which is often applied to the design of computer systems. In considering these goals, it is useful to realize that there may be tradeoffs between them. For example, performance is an all-encompassing term that may involve the reduction of errors or an increase in productivity i.
Hence, enhanced productivity may sometimes cause more opera- tor errors, potentially compromising safety. As another example, some compa- nies may decide to cut corners on time-consuming safety procedures in order to meet productivity goals. Fortunately, however, these tradeoffs are not inevitable. Human factors interventions often can satisfy both goals at once Hendrick, ; Alexander, Workers were more able to continue work increasing productivity , while greatly reducing the risk of in- jury increasing safety.
In the most general sense, the three goals of human factors are accom- plished through several procedures in the human factors cycle, illustrated in Figure 1, which depicts the human operator brain and body and the system with which he or she is interacting. At point A, it is necessary to diagnose or identify the problems and deficiencies in the human—system interaction of an existing system. To do this effectively, core knowledge of the nature of the physical body its size, shape, and strength and of the mind its information-processing.
Point A identifies a cycle when human factors solutions are sought because a problem e. Point B identifies a point where good human factors are applied at the beginning of a design cycle. For example, why did the worker in our first story suffer the back injury? Was it the amount of the load or the awkward position required to lift it? Was this worker representative of others who also might suffer injury? Having identified the problem, the five different approaches shown at point B may be directed toward implementing a solution Booher, , , as shown at the bottom of the figure.
Equipment design changes the nature of the physical equipment with which humans work. The medicine bottle in our example could be given a more read- able label and an easier-to-open top. The radar display on the USS Vincennes might be redesigned to provide a more integrated representation of lateral and vertical motion of the aircraft. Task design focuses more on changing what operators do than on changing the devices they use. The workstation for the assembly-line worker might be re- designed to eliminate manual lifting.
Task design may involve assigning part or. For example, a robot might be designed to accomplish the lift of the component. Of course, automa- tion is not always the answer, as illustrated by the example of the automated voice response system.
Environmental design implements changes, such as improved lighting, tem- perature control, and reduced noise in the physical environment where the task is carried out. A broader view of the environment could also include the organi- zational climate within which the work is performed.
This might, for example, represent a change in management structure to allow workers more participa- tion in implementing safety programs or other changes in the organization. Training focuses on better preparing the worker for the conditions that he or she will encounter in the job environment by teaching and practicing the nec- essary physical or mental skills.
Selection is a technique that recognizes the individual differences across hu- mans in almost every physical and mental dimension that is relevant for good system performance.
Such performance can be optimized by selecting operators who possess the best profile of characteristics for the job. For example, the lower-back injury in our leading scenario might have been caused by asking a worker who had neither the necessary physical strength nor the body proportion to lift the component in a safe manner.
The accident could have been prevented with a more stringent operator-selection process. Our discussion has focused on fixing systems that are defi- cient, that is, intervening at point A in Figure 1. In fact, the practice of good human factors is just as relevant to designing systems that are effective at the start and thereby anticipating and avoiding the human factors deficiencies be- fore they are inflicted on system design. Thus, the role of human factors in the design loop can just as easily enter at point B as at point A.
If consideration for good human factors is given early in the design process, considerable savings in both money and possibly human suffering can be achieved Booher, ; Hen- drick, Alexander has estimated that the percentage cost to an organization of incorporating human factors in design grows from 2 percent of the total product cost when human factors is ad- dressed at the earliest stages and incidents like workplace accidents are pre- vented to between 5 percent and 20 percent when human factors is addressed only in response to those accidents, after a product is fully within the manufac- turing stage.
The Scope of Human Factors While the field of human factors originally grew out of a fairly narrow concern for human interaction with physical devices usually military or industrial , its scope has broadened greatly during the last few decades. Membership in the pri-. A survey indicates that these membership numbers may greatly underestimate the number of people in the workplace who actually consider themselves as doing human factors work Williges, This growth plus the fact that the practice of human factors is goal-oriented rather than content-oriented means that the precise boundaries of the discipline of human factors cannot be tightly defined.
One way of understanding what human factors professionals do is illustrated in Figure 2. Across the top of the matrix is an incomplete list of the major categories of systems that define the environments or contexts within which the human operates.
On the left are those system environments in which the focus is the individual operator. Major categories include the industrial environment e.
On the right are those environments that focus on the interaction between. Muscular Strength Other Biological Factors. FIGURE 2 This matrix of human factors topics depicts human performance issues against contextual environments within which human factors may be applied. The study of human factors may legitimately belong within any cell or combination of cells in the matrix. A distinction can be made between the focus on teams involved in a cooperative project and organizations, a focus that involves a wider concern with management structure.
Figure 2 lists various components of the human user that are called on by the system in question. Is the information necessary to perform the task visible? Can it be sensed and adequately perceived? These components were inadequate for the elderly woman in the second example. What communications and cogni- tive processes are involved in understanding the information and deciding what to do with it?
Decisions on the USS Vincennes suffered because personnel did not correctly understand the situation due to ambiguous communications. How are actions to be carried out, and what are the physical and muscular demands of those actions?
What is the role of other biological factors related to things like ill- ness and fatigue? As shown at the far left of the figure, all of these processes may be influenced by stresses imposed on the human operator, by training, and by the individual differences in component skill and strength.
Thus, any given task environment listed across the top of the matrix may rely upon some subset of human components listed down the side.
A critical role of task analysis that we discuss is to identify the mapping from tasks to human components and thereby to define the scope of human factors for any particular application. A second way of looking at the scope of human factors is to consider the re- lationship of the discipline with other related domains of science and engineer- ing.
This is shown in Figure 3. Items within the figure are placed close to other items to which they are related. The core discipline of human factors is shown at the center of the circle, and immediately surrounding it are various subdomains of study within human factors; these are boldfaced.
Surrounding these are disci- plines within the study of psychology on the top and engineering toward the bottom that intersect with human factors.
At the bottom of the figure are domain-specific engineering disciplines, each of which focuses on a particular kind of system that itself has human factors components. Finally, outside of the circle are other disciplines that also overlap with some aspects of human factors. Closely related to human factors are ergonomics, engineering psychology, and cognitive engineering. Historically, the study of ergonomics has focused on the aspect of human factors related to physical work Grandjean, This discipline is often closely related to aspects of human physiology, hence its closeness to the study of biological psychology and bioengineering.
Ergonomics has also been the preferred label in Europe to de- scribe all aspects of human factors. However, in practice the domains of human factors and ergonomics have been sufficiently blended on both sides of the At- lantic so that the distinction is often not maintained.
Engineering psychology is a discipline within psychology, whereas the study of human factors is a discipline within engineering. The distinction is clear: The ultimate goal of the study of human factors is toward system design, accounting for those factors, psychological and physical, that are properties of the human.
But this dis- tinction is certainly not a hard and fast one. Cognitive engineering. In essence. In that sense.
Those more closely related to psychology are shown at the top. In contrast. Sanders and Mc- Cormick As an example.
Norman examines human factors manifestations in the kinds of consumer systems that most of us encounter 8. Researchers have learned that the most effective understanding. A critical element to achieving effective generalization and prediction is the nature of the observation or study of the human operator.
It also is important to be able to predict that solutions designed to create good human factors will actually succeed when put into practice. In the problem diagnosis phase Figure 1 in- vestigators wish to generalize across classes of problems that may have common elements. Such generalization is more effective when it is based on a deep understanding of the physical and mental components of the human operator.
Humans can be stud- ied in a range of environments. Bailey Introduction to Human Factors every day. In complementary fashion. Human Factors. Ergonomics in Design. Wilson and Corlett Wickens and Hollands provide coverage of engineering psychology. Several journals address human factors issues. He thought his customers only cared about the music. Sallie Gordon Becker.
Edison thought he could save considerable money at no sac- rifice to quality by recording those lesser-known artists. Edison scoffed at the scratchy sound of the disc compared to the superior sound of his cylinders.
Edison invented it. The moral of this story is to know your customer. John Lee. Many technology-oriented companies are in a simi- lar muddle. He was right. Edison decided that big-name. The problem was. Consider the phonograph. Once again. Design and Evaluation Methods T homas Edison was a great inventor but a poor businessman.
Yili Liu. Edison thought phonographs could lead to a paperless office in which dictated letters could be recorded and the cylinders mailed to the recipients without the need for transcrip- tion. Edison pitted his taste and his technology-centered analysis on belief that the difference was not important: He lost. Second Edition. They develop technology-driven products.
He is probably correct. The real use of the phonograph. Adapted from Norman. Being first. In this chapter.
Although interface design may be the most visible design element. In a book that every engineer should read. Designers tend to focus pri- marily on the technology and its features without fully considering the use of the product from the human point of view.
Norman writes congently. Why do we put up with the frustrations of everyday objects. The mate- rial in this chapter provides an overview of the human factors process. In addition to conducting basic and applied research to broaden our understanding. Human factors methods and principles are applied in all product design phases: Design and Evaluation Methods The goal of a human factors specialist is to make systems successful by en- hancing performance.
For example. It is best if the designer errs on the con- servative side in making these assumptions. The process of bringing human factors analysis in at the end of the product design phase inherently places everyone involved at odds with one another. Human factors can ultimately save companies time and money. It is not hard to understand why engineers are less than thrilled to receive the results of a human factors analysis.
Poor design is common. A human factors expert may be asked to somehow justify his or her involvement in a proj- ect and explicitly demonstrate a need for the extra expense.
In most instances. In this case. But to max- imize the benefits achieved by applying human factors methods.
Design and Evaluation Methods washing machines and dryers that have become too confusing to use. Mayhew provides a simple example of such an analysis.
Table 1 shows a hypothet- ical example of the costs of conducting a usability study for a software proto- type. Some types of benefits are more common for one type of manufacturer or customer than another. Even when designers attempt to consider human factors. They have invested in the design. This expert is then placed in the unenviable position of having to come back with criticisms of a design that a person or design team has probably spent months and many thousands of dollars to develop.
Mayhew gives an example for a human factors software Other quantifiable benefits are health or safety related Alexander. Englewood Cliffs. Adapted by permission. Estimating the dollar value of averting such catastrophic failures can be quite difficult. These numbers are multiplied by the number of times the tasks are performed and by the number of people performing the task e.
The difference is then calculated. Prentice Hall. The same variables are then estimated. The estimated benefit is the total cost savings between the two. The total benefit of the effort is determined by first estimating values for the relevant variables without human factors intervention.
Principles and guidelines in software user interface design. Mayhew lists nine benefits that might be applicable and that can be estimated quantita- tively: The same values are estimated for performance if a human factors effort is conducted. It is easy to see that even small cost savings per task can add up over the course of a year. Product design models are all relatively similar and include stages reflecting pre- design or front-end analysis activities.
There are numerous systematic design models. Human Factors in the Product Design Lifecycle One major goal in human factors is to support the design of products in a cost- effective and timely fashion. Mantei and Teorey Table 2 shows the estimated benefits.. Karat reports a case where human factors was performed for development of software used by Product lifecycle models also add product implementa- tion. Marcotte et al. As noted earlier. Dix et al. Design and Evaluation Methods analysis that would be expected to decrease the throughput time for fill-in screens by three seconds per screen.
Refer to Alexander Bias and Mayhew Manufacturing plants can like- wise make gains by reducing costs associated with product assembly and main- tenance e. As we will describe in the following pages.
The most effective way to involve human factors in product design is to have multidisciplinary design team members working together from the beginning. User-Centered Design All of the specific human factors methods and techniques that we will review shortly are ways to carry out the overriding methodological principle in the field of human factors: For a human factors specialist.
Team members often include personnel from marketing. Design and Evaluation Methods below. Usability engineering has been most rigorously developed for software design e. User-centered design does not mean that the user designs the product or has control of the design process.
Before describing these six stages in detail. Wiklund How do we put this princi- ple into practice? Primarily by adequately determining user needs and by involv- ing the user at all stages of the design process. For large-scale projects. Data Compendiums. This standard provides detailed requirements for areas such as controls.
It is important to point out that many guidelines are just that: One form consists of condensed and categorized databases. The designer must look to more abstract principles and guidelines for this information.
Existing standards do not provide so- lutions for all design problems. Human Factors Design Standards. Department of Defense. Human Factors Principles and Guidelines. Human factors principles and guidelines cover a wide range of topics.
Standards are precise rec- ommendations that relate to very specific areas or topics. Donald Norman gives princi- ples for designing products that are easy to use Norman. Such information is being developed in several forms.
Campbell et al. Both contain two types of specifications: Some guidelines pertain to the design of physical facilities e. An example is the four- volume publication by Boff and Lincoln Other guidelines focus on information systems in cars Campbell et al.
Engineering Data Compendium: Human Perception and Performance.. Another form of information to support de- sign is engineering or human factors design standards. Most guidelines require careful consideration and ap- plication by designers. Boff et al. As the field of human factors has matured. Design and Evaluation Methods Sources for Design Work Human factors specialists usually rely on several sources of information to guide their involvement in the design process.
On the very general end. A persona is a hypothetical person developed through interviews and observations of real people. After identifying characteristics of the user popu- lation. This includes not only users in the traditional sense. This usually includes characteristics such as age. It is important to create a complete description of the potential user popu- lation. This is not an appropriate analysis if the goal is to attract. What tasks must be performed?
De- signing for an elastic user may create a product that fails to satisfy any real user. Even if user characteristics are identified. Not all of the activities are carried out in de- tail for every project. For situations where products or systems already exist. User Analysis Before any other analysis is conducted. These questions are answered by performing various analyses.
What are the major functions to be performed by the system. No- tice. Personas Cooper developed the concept of personas to represent the user charac- teristics in a concrete and understandable manner.
The personas exist to define the goals that the system must support and describe the capabilities and limits of users in concrete terms. Task analysis is one of the most important tools for understand- ing the user and can vary substantially in its level of detail. Task Analysis.. For most applications. Depending on the nature of the system being designed. Activi- ties or basic tasks that are identified in the task analysis should be described with respect to the specific environment in which the activities are performed Wixon et al.
Separate personas may be needed to describe people with other roles in the system. The persona should be specific to the point of having a name. The functional de- scription lists the general categories of functions served by the system. The description of the persona includes not only physical characteristics and abilities.
Environment Analysis In most cases. The preliminary task analysis traditionally specifies the jobs. Once the population of potential users has been identified. The environment analysis can be performed concurrently with the user and task analysis. Function Analysis. Functions represent general transformations of information and system state that help people achieve their goals but do not specify particular tasks.
Design and Evaluation Methods are not real people. Personas enable programmers and other members of the design team to think about specific user characteristics and prevent the nat- ural tendency to assume users are like themselves. The tasks should be specific enough to include the types of cuts. A goal is an end condition or reason for performing the tasks.
How to Perform a Task Analysis Most generally. A more detailed task list would describe the subtasks involved in opening the letter. Goals do not de- pend on technology.
Design and Evaluation Methods the saw.
In general. As a simple example. Often it is difficult to discriminate the function list from the preliminary task list because the preliminary task list does not provide a detailed description of what the person actually does. It is not unusual for ergonomists to spend several months performing this analysis for a product or system.
A task analysis for a digital camera might first specify the different types of photos reg- ularly taken by people—group snapshots. The analysis would result in an information base that includes user goals. The following steps describe the basic elements of a task analysis: Functions represent the general transformations needed to achieve the goal. The short list of a preliminary task analysis is often adequate at the beginning of the design process.
Both the purpose and the type of the task will influence the information gathered. Describing the hierarchical rela- tionships between functions. Define Purpose and Required Data. The first step of task analysis is to define what design considerations the task analysis is to address. Design and Evaluation Methods Kirwan and Ainsworth provide an exhaustive description of task analysis techniques. Typical reasons for performing a task analysis include defining training requirements.
A second important type of information in describing tasks is information flow. A particularly im- portant type of information collected in many task analyses is the hierarchical relationships.
In this situation. While many methods are currently being developed specifically for cognitive task analysis. For some systems. Hierarchical grouping of functions. With the camera example.
In other systems. Because an increasing number of jobs have a large proportion of cog- nitive subtasks. Because a task analysis can be quite time consuming. Tasks can be physical tasks. The physical space can also have a surprisingly large effect on computer-based work. Location of equipment can greatly influence the effectiveness of people in production-line settings. Task sequence information can be particularly useful in determining how long a set of tasks will take to complete or in estimating the number of people required to complete them.
One of the best resources is Kirwan and Ainsworth A third type of information describing tasks is the task sequence. In the camera example.
Schraagen et al describe several Most im- portantly. Specific task sequence informa- tion includes the goal or intent of task. After the purpose of the task analysis is defined and relevant data identified. A Guidebook to Task Analysis. A fourth type of information describing tasks is the location and environ- mental conditions. Performed in a different order. These four categories describe tasks from a different perspective and are all required for a comprehensive task analysis.
Many methods exist to support these steps. Design and Evaluation Methods uals and their roles can identify important design considerations regarding the flow of information and resources that might otherwise go unnoticed.
Other useful information can be in- cluded in these four categories. This is not always possible.
One of the most useful data collection methods is to observe users using existing versions of the product or system if such systems exist Niel- son. Collect Task Data A task analysis is conducted by interacting extensively with multiple users Dia- per. Think-Aloud Verbal Protocol. It is often difficult for users to imagine and de- scribe how they would perform a given task or activity. Verbal protocols are usually one of three types: System users are asked to perform the activities under a variety of typical scenarios.
It is important to identify different methods for accomplishing a goal rather than identifying only the one typically used by a person. Task analysis tends to be characterized by periods of data collection. In addi- tion. Many researchers and designers conduct task analyses by having users think out loud as they perform various tasks.
This yields insight into underlying goals. The following methods can be used in any combination during this itera- tive process. There are a wide range of methods currently in use. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime. Upcoming SlideShare.
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