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Ergonomic and Usability Analysis and Evaluation Alexandra Burn, Eunice Ji, Austin Lin, Brooke Mayer, and Samantha Skarin Professor Alan Hedge
DEA 470: Applied Ergonomic Methods Spring 2008
TABLE O
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ONTENTS
Abstract
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Introduction
4
Methods
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Results
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Discussion
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Acknowledgements
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References
21
Appendix
22
Bloopers
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DEA 470: Applied Ergonomic Methods
Spring 2008
ABSTRACT
Many devices claim to be ergonomic, however there have been few studies comparing task performance and musculoskeletal comfort with the claimed benefits of the manufacturers. In this study, we measure the performance of an input device as well as the ergonomic benefits and user preferences of the device. Performance was measured through a Fitts’ Law test application, posture was analyzed with goniometer measurements of wrist extension/flexion, wrist deviation, and arm flexion/abduction. A repeated subjects comparison test with three other types of input devices was conducted. It was found that the Quill showed response times which were longer than average in the Fitts’ Law test application, higher levels of radial and ulnar deviation, and higher levels of wrist extension/flexion.
Vertical is good. Gripless is better!
Figure 1 | The Quill Box
The Quill: Ergonomic and Usability Analysis and Evaluation
INTRO DU CTI ON The Quill Mouse (now known as the AirO2bic™ mouse) was developed in the United Kingdom by Designer Appliances Incorporated. Designer Appliances Incorporated claims that this mouse is the first “biomechanically designed” mouse and it was designed with the intention of preventing carpel tunnel syndrome and other musculoskeletal disorders. The design is said to “reduce biomechanical load on muscles and nerves and to be the only mouse that is “gripless” whereas standard horizontal mice require a pinch grip, and certain vertical mouse types require the use of the power grip. The mouse comes in a right-handed version and a left-handed version and is available in onyx (black) and pearl (white) (figure 2). Included with the mouse is an instructional booklet
Figure 2 | Quill Mouse in Onyx Right-Handed and Pearl Left-Handed
DEA 470: Applied Ergonomic Methods
explaining the correct way of using both the left and righthanded mouse as well as notes on getting used to the mouse and the most effective way to position yourself at a computer workstation to avoid injury. Also included is software to be used in conjunction with The Quill. The first program is the Quilltimer which appears on the computer desktop and after an hour and 45 minutes of work, alerts the user that in accordance with OSHA (Occupational Safety and Health Administration) standards, the user should take a 15 minute break from mousing so as to aide in the prevention of injury. The other program included is The Median Nerve Challenge which evaluates personal median mobility through a “simple exercise”. According to the instructional booklet included with the Quill, the proper way to use the device is for the user to place his or her fingers and palm on the “button mound” (the right hand if the user is right-handed and using the right-handed version of the mouse, the left if the user is left-handed and using the left-handed version of the mouse) and rest his or her wrist and forearm into the “wrist forearm guide”. The thumb is left to rest as is most comfortable for the user on the other side of the button mound. On the right-handed mouse, the top button corresponds with the right-click button on a standard mouse, and the bottom button corresponds with the leftclick button on a standard mouse. On the left-handed mouse, the top button corresponds with the right-click button on a standard mouse, and the bottom button corresponds with the left-click button on a standard mouse. This configuration is stated to be what will come naturally
Spring 2008
ODUCTION INTR
to users of the Quill. The design and materials of an input device contribute to its usability and aesthetics. The Quill requires users to make a slight grip. It has been shown that people prefer the soft feel of foam to hard, smooth wood or metal because foam increases the uniformity of force distribution from the hand, thus improving user comfort. [3] Tool handles and computer input devices have different design implications, however, the part about adding foam rubber to the contact areas to decrease slippage and discomfort may be relevant to input devices such as the Quill that actually requires a slight pinch grip. Intensive computer mouse users are at increased risk for carpal tunnel syndrome and other upper extremity musculoskeletal disorders. Computer users generally spend one to two-thirds of their computer work using the mouse. Postures that greatly deviate from neutral wrist and shoulder positions are maintained for a greater percentage of time while people use the mouse than using the keyboard [7]. Hedge et. al (1999) used two mice, one palm-down with a curved design to reduce ulnar deviation and the other a larger, flatter mouse that had built in wrist support, to observe the differences in wrist posture with men and women in the 95th, 50th, and 5th percentiles. Their results showed an average 8 degree lower wrist extension with the wrist supporting mouse (18.3) than the curved mouse (26.5). The design of the wrist-supporting mouse reduced
wrist extension and moved the average wrist extension from outside a neutral zone of movement (>20Âş) to being inside this zone. As this mouse supports the wrist, subjects in this study found fine hand movements much more difficult with this mouse than with the curved mouse. Both of these results have implications on the use of the Quill as it also supports the wrist and although it may keep wrist extension low, it may be hard for the user to make fine hand movements. High muscular load in the forearm muscles is associated with musculoskeletal discomfort. Most palmdown mice are held with a pronated forearm and moved with wrist movements, and studies have shown that palmdown mouse users are at risk for extreme ulnar deviation of the wrist, all of which pose potential risk factor for musculoskeletal disorders of the wrist, elbow, and forearm [9]. As the Quill uses a vertical hand alignment, the wrist is less pronated (figure 3, next page). In a study done on the muscle load on the forearm with a palm-down mouse compared to a vertical mouse a vertical mouse was moved mainly by whole arm movements and used an almost neutral hand position [1]. They also found that the muscle load on the forearm was significantly less with use of the vertical mouse. A similar study by Gustafsson et. al found that there was less ulnar deviation when using a neutral, vertical mouse than when using a palm-down pronated mouse. This study also measured decreased muscular activity in the forearm with the vertical mouse as well as a lower perceived exertion in the shoulder and wrist. These studies have implications for the Quill mouse as it also The Quill: Ergonomic and Usability Analysis and Evaluation
“Computer users generally spend one to two thirds of their computer work using the mouse�
INTRO DU CTI ON utilizes a neutral posture due to its grip-less design. It would follow that the Quill would also require a lesser muscle load in the forearm and less ulnar deviation and pronation than a palm-down mouse and so would decrease musculoskeletal discomfort. Additionally significant increase in carpal tunnel pressure was observed when using a mouse as opposed to resting the hand on the mouse and concludes that using a mouse for long duration may expose some individuals to carpal tunnel pressure levels that may lead to carpal tunnel syndrome [7]. Wrist extension and ulnar deviation cause increased pressure on the median nerve by narrowing the carpal tunnel [2]. Increased neural tension in the median and radial nerves is caused by extension and ulnar deviation respectively, and both postures necessarily involve activation of forearm muscles while shortened. Postures involving wrist extension and ulnar deviation have been associated with discomfort and musculoskeletal disorders.
measuring number of successful hits [4, 8]. In this study we use a modified Fitts’ test to measure performance while using the Quill mouse.
Fitts’ Law is a model of human motor response that predicts the amount of time that it takes to move to a target area in terms of the size and distance of the target. The speed at which a user can point to the target is inversely related to the accuracy at which they can point to the target; targets that are of smaller size and farther away require the most time while targets of larger size and closer require less time to acquire. Fitts’ original experiments involved tapping tasks where with two rectangular targets of different sizes and at varying distances. The controlled variables were target width and the distance between targets
DEA 470: Applied Ergonomic Methods
Spring 2008
Figure 3 | Vertical Hand Placement in the Quill
METHODS
Design In this study we measured the performance, posture and preference of four different ergonomic input devices. Students were instructed to complete a Fitts’ Law test using four different mice in four separate trials. In each of these trials, we measured the posture of the participants before and during the test. The user’s arm abduction angle (figure 4) and forward flexion angle (figure 5) were measured with goniometers to determine the posture of the participant.
The wrist extension, wrist flexion, radial deviation and ulnar deviation were measured during the Fitts’ Law test to determine the effect of the input device on wrist placement and posture (figures 6 & 7). The Fitts’ Law test was administered through a web-based Java application (http:// www.tele-actor.net/cgi-bin/fitts/applet2.pl) that measured the average response time to click on a series of 25 circular targets. The targets varied randomly in size and location. This differs from Fitts’ original test in that the targets could be located within a circular radius of a central target
Figure 6 | Wrist Extension and Flexion Figure 4 | Arm Abduction
Figure 5 | Forward Flexion
Figure 7 | Radial and Ulnar Deviation The Quill: Ergonomic and Usability Analysis and Evaluation
METH O
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involving a two-dimensional movement (figures 8 & 9). After participants performed the experiment with all four mice, they completed the post-test user experience survey from which we determined preferences. A pre-test survey and a post-test survey were given to determine existing user data as well as preferences for certain input devices. Participants/Subjects Participants were selected from a group of student volunteers in a college ergonomics course. Ages varied from 19-23 with an even distribution of males and females. Participants had no previous experimental experience in a mouse input device study. Apparatus/Setting
Figure 8 | Screenshot of Fitts’ Test In Game
Pre-test Survey: (refer to Appendix A) This survey was administered to each participant before taking the Fitts’ Law test. This survey determined handedness, history of previous use, and the initial appeal of the input devices being tested as a standardizing mechanism. This survey ensured that all participants began the study at a similar level of knowledge. Electrogoniometer: An electrogoniometer was attached to the posterior of the right wrist at neutral posture. The sensor was oriented parallel to the forearm and placed equidistant from each side of the forearm (figure 10).
DEA 470: Applied Ergonomic Methods
Spring 2008
Figure 9 | Screenshot of Fitts’ Test Final
METHODS
Tape Measure/Goniometer: These devices were used after each participant was seated in a chair and asked to place their right hand on the input device in the way that they thought appropriate. They were then instructed on the intended way to hold the device. While in this posture, a goniometer and tape measure were used to measure the participant’s arm abduction angle and forward flexion angle (figures 11 & 12).
Post-test Survey: (refer to Appendix B) This survey was administered to each participant immediately after completing the Fitts’ Law test trial on each device. This survey measured post-use comfort level rating, aesthetic preference, ease of use, and overall preference.
Equipment: - tape measure - goniometer - electrogoniometer - dell 14” notebooks - the Quill and other input devices
Dell 14” Notebook and Input Devices (The Quill, Perific, Wow, and Switch): Used for testing the input devices with the Fitts’ Law Test on the Dell Notebooks.
Figures 11 & 12 | Measurements Taken with Tape Measure and Goniometer
Figure 10 | Setup with Goniometer Attached The Quill: Ergonomic and Usability Analysis and Evaluation
METH O
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Procedure Users were first given the pre-test survey (see Appendix A) before the experiment began. The electrogoniometers were attached to the users’ wrists; users were asked to place their hand flat on the table in order to calibrate the electrogoniometers to neutral posture. The form in which users intuitively placed their hand on the mouse in the position was noted. Measurements of upper limp posture and hand size were taken with goniometers and tape measure. The instructions for using the mouse properly were read to the user. Test administrators gave a brief explanation of the Fitts’ Law test application in which the user would repeatedly click on a green target which would change in size and distance. After users completed the test, their average reaction times as given by the test program, were recorded. Each user completed four trials the Fitts’ Law test application with all four types of input devices on the same computer and calibrated to the same electrogoniometer. After all of the trials the post-test user experience survey was given (see Appendix B).
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DEA 470: Applied Ergonomic Methods
Spring 2008
RESULTS
Performance Performance Measures: The Fitts’ Law test application used in this study scored performance by participant response time. Game scores were based on a time trial and the final game score represents the time (ms) it took to complete the Fitts’ task. While each participant hit the same number of targets in each task, it was the time period that varied between input devices. Trials with the Quill on average yielded longer
response times in comparison to the average response times for the other input devices (Appendix C, figure 13). A paired sample t-test indicated that there was a significant difference between the game scores of the Quill and the Wow (paired t-test: t=4.510, df=3, p=.020) but not between the Quill and the Switch or between the Quill and the Perific (refer to Appendix D). Performance Observations: On multiple occasions, participants were observed
The Quill produced an average 73 points higher than any other device
Figure 13 | Graph of User Performance with Various Input Devices The Quill: Ergonomic and Usability Analysis and Evaluation
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R ES U
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lifting the entire mouse back to the center of their maneuvering space on the work surface, as they’d lost the cursor to the edge of the computer screen. This frustrated users and was remarked upon on two instances during the fitts’ trials. Throughout the task, users were also observed remarking on the need to “move your whole arm” in order to maneuver the mouse. These two factors, 1) the need to lift the mouse off of the table to return it to a workable surface, and 2) the need to move the entire arm in order to maneuver the device, held obvious negative effects on
response time for the Quill. Posture and Ergonomics The Quill Fitts’ trials exhibited a significantly higher presence of radial and ulnar deviation than did the other input devices (Appendix C, figure 14). While the average level of radial/ulnar deviation was greater in the trials with the Quill in comparison to all other devices, these levels were only significantly higher than the Wow (paired t-
Figure 14 | Graph of Mean Radial/Ulnar Deviation 12
DEA 470: Applied Ergonomic Methods
Spring 2008
RESULTS
test: t=3.372, df=3, p=.043) and the Switch (paired t-test: t=4.310, df=3, p=.023). Contrastingly, on average the trials on the Quill exhibited lower levels of extension and flexion then did the other input devices, excluding the switch (Appendix C, figure 15). A paired sample t-test, however, indicated that the mean extension/flexion exhibited in the quill was only significantly lower than the Wow (paired ttest: t=-3.464, df=3, p=.041) and not the Perific. The mean extension/flexion for the quill was found to be significantly higher than that exhibited with the switch (paired t-test: t=7.011, df=3, p=.006)(refer to Appendix D).
Additional Postural Observations In addition to the electrogoniometer measures, participant posture was visually observed and recorded while fitts’ trials took place. Recurring, non-neutral postural trends observed included the lifting of the middle finger while operating the Quill. This lifting action most likely contributed to the increased Ulnar/Radial deviation as this type of lifting can create strain in the Radial and Ulnar nerves.
Figure 15 | Graph of Mean Arm Extension/Flexion The Quill: Ergonomic and Usability Analysis and Evaluation
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User Survey
“ You have to use your entire arm to move this mouse”
The user surveys yielded a wide range of opinions about the design of the Quill. Each question also took the participants’ preferences for a traditional mouse into account as a standard to measure against. Data collected from the post-test user survey indicated that participants
generally felt the quill to be the least comfortable device of the four that were tested (figure 16). Remarks from the participants that lend support to this finding were recorded during the fitts’ trials: “I feel like my fingers should be further up” or “you have to move your entire arm to move this mouse,” or “I usually click the right click button with my middle finger but on this mouse I can’t do that.”
Figure 16 | Graph of Mean Comfort Ratings 14
DEA 470: Applied Ergonomic Methods
Spring 2008
RESULTS
Preference for aesthetic and design were also collected from this survey. The Quill was drastically awarded the lowest aesthetic preference of the four devices (figure 17). Recorded remarks included claims that the Quill looked “too heavy” or “bulky” in comparison to some of the more sleek designs being tested. In addition to comfort and aesthetic preferences, the surveys measured
participants’ rating of ease of use with each device. Again, the Quill rated low. Of the four input devices, participants rated the Quill as the most difficult to use (figure 18, next page). This finding, too, was supported by verbal remarks recording during the Fitts’ trials; complaints regarding accuracy and speed with which one could move the device were prevalent. In a survey question aimed to determine
Figure 17 | Graph of Mean Aesthetic Preference The Quill: Ergonomic and Usability Analysis and Evaluation
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the participants’ overall preference for the input devices, the Quill averaged zero preference; no participants chose the Quill as their preferred device. Of seven participants, two preferred the Wow, one preferred the Switch, two preferred the Perrific, and two preferred the traditional mouse.
Figure 18 | Graph of Mean Ease of Use Rating 16
DEA 470: Applied Ergonomic Methods
Spring 2008
DISCUSSION
The designers of the Quill claim that it will provide biomechanical benefits by “reducing the load on the mousing limb.” It claims to keep the wrist in an orthopedically neutral or untwisted position so taking advantage of these benefits requires no conscious effort by the user. The heel and sidewall of the mouse stop the wrist flexing both vertically and horizontally and allow for a “grip-less” grip. As the user does not need to grip the mouse in a traditional pinch or power grip, the muscles of the hand will be kept in a neutral posture and almost zero force is required of the hand muscles. The manual also claims that there is an acclimatization period when a person begins using the mouse that may result in sweaty hands or new sensations in the large muscle groups of their mousing limb, but these symptoms will disappear after the body has become acclimatized to the Quill. In terms of performance compared to the other three devices, the Quill was generally associated with a longer task completion time, which was indicated by the game score. Due to the small size of the sample, it is difficult to establish a causal relation between the use of the Quill and slower performance. It is, however, reasonable to suggest that the Quill is not an ideal device for tasks of this sort. Also, considering that the subjects did not have previous experience with any of the four input devices or the Fitts’ Law test application, we can disregard any effect of confounding variables that might have led to such results. In addition, prior to the experiment, the subjects were given instructions on how their devices should be used and were corrected if they deviated. This indicates for the
possibility that the design of the Quill has anthropometric issues that may have delayed the subjects’ performance. Most palm-down mouse types require the user to use a pinch grip on the mouse, holding it between the thumb and one or more forefingers. Excessive finger pressure can lead to strain and injury in the finger and into the tendons. Some vertical mouse types use a power grip, where the muscles of the hand and forearm are used to wrap the hand around the mouse. The Quill keeps the hand in a neutral posture as the hand is not actively using muscles to grip the mouse. This means that the force applied is low to zero.
“The Quill keeps the hand in a neutral posture as the hand is not actively using muscles to grip the mouse”
Figure 19 | Participant’s Hand in Mouse The Quill: Ergonomic and Usability Analysis and Evaluation
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DISCU S SI ON
None of the five participants rated the Quill as their most preferred...
During the testing we observed several anthropometric issues with the Quill. Since the pinky finger is positioned on the “wrist forearm guide” with the ring, middle, and index fingers placed on top of it, the pinky finger may begin to ache after long periods of mousing. Also, the Quill sometimes had to be lifted up from the work surface due to the lack of space on the table. This is an important concern considering that many work surfaces do not allot sufficient real estate for input devices. For some desk systems containing trays for input devices, users may find it difficult to manipulate the Quill within the tray. The risk of potential wrist deviation due to lack of space was also raised. When a subject’s forearm is not flat on the table but is pulled to the back towards the body, the subject’s wrist is likely to bend around the edge of the table surface. This is a deviation from the neutral wrist position. As we have mentioned in the beginning of the report, prolonged or repetitive exposure to postures involving deviation from neutral joint positions may lead to musculoskeletal discomfort and injury. Additionally, the design of the Quill does not seem to have taken in account the anthropometric differences in hand size and finger dimensions. As a result, some user groups such as children with smaller grip size may find the Quill difficult to maneuver. None of the five participants rated the Quill as their most preferred which speaks to its aesthetics and impressions in the short trial period. There are several design changes that can be made in the next iteration of the Quill in order to make it more user friendly and ergonomic.
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There were several times that users tried to reposition the mouse on the table by lifting it up. One reason for this is because the device had a large footprint which hinders users with limited table space. Due to the “gripless” design of the Quill it is very strenuous to lift vertically; this could be improved if there was an indentation in which the thumb could rest. During our tests users noted that their hands became sweaty due to poor circulation while using the Quill. The mouse can be coated with a “soft touch” material to improve comfort as well as aesthetics. Buttons positioned such that when pressed, the force is towards the users body instead of to the left (for the right-handed mouse) or to the right (for the left-handed mouse) of the user. This will improve cursor accuracy because currently when buttons are pushed towards the right or left, the entire mouse may move thus moving the cursor on the screen off of the desired target. While the Fitts’ Law test application measures sheer target acquisition performance, an extended use study can be conducted to measure performance of input devices in real life use environments. Further studies can also be done comparing traditional mice to the highest performing and most ergonomic input devices in this study. In the pre-test survey over 40% of the users said that they used a touchpad most often; there have been few improvements on touchpads since their introduction. This is another area that could definitely use an ergonomic perspective as touchpads have become the dominant input device on laptop computers. One of the users noted that while they were left handed, they had learned to use their right hand
Spring 2008
DISCUSSION
for computer input. It would be very interesting to determine how this affects their response time and cognitive perception. Weaknesses of study/experiment Our experiment contains several weaknesses that may have influenced the final outcomes. The sample consisted of only four subjects. This was due to the time constraint and the unforeseen malfunction of the electrogoniometer that delayed the progress of the experiment and led us to eliminate the data from certain subjects. Therefore, the data of the game scores and the wrist deviations may not be representative of the general population and statistically significant. In addition, the subjects were recruited from a pool of college students in an ergonomics course. The anthropometric characteristics of the participants are not representative of the general population. Some pre-test bias was observed. One of the subjects indicated that he/she frequently plays computer games (~20 hours per week), suggesting a possible effect of extra practice with computer input devices. In addition, some of the participants may have used the devices when they were allowed to experiment with them in the initial stage of this assignment. Although their previous exposure to the tested devices is likely to be minimal, this pre-test bias may have influenced the test results. In the future, it is important to conduct the experiment using a larger sample that is representative of the general population. Better assessment of participants’ previous experience with computer input devices is needed to control for outliers.
The Quill: Ergonomic and Usability Analysis and Evaluation
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GEMENT
S
ACKN OW LED
Alexandra, Eunice, Austin, Brooke and Samantha would like to thank everyone who helped during the development of this report. We would like to thank the other members of DEA 470 for their assistance and participation during testing and the gathering of results. We would especially like to thank Kelly Wilson for her assistance with the statistics for our report, without which we may have been completely lost. Lastly, we would like to thank Alan Hedge and Alisha Belk for giving us this amazing learning experience and helping us along the way.
Thank You!
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REFERENCES
1. Aaras ,A., and O. Ro. “Workload when using a mouse as an input device.” International Journal of Human Computer Interaction 9.2 (1997):105-118. 2. Burgess-Limerick, R., Shemmel, J., Scadden, R., & Plooy, A. Wrist posture during computer pointing device use. Clinical Biomechanics, 14, (1999): 280-286. 3. Fellows, G. L. and Freivalds, A. Ergonomics evaluation of a foam rubber grip for tool handles. Applied Ergonomics. 22 (4), (1991): 225-230. 4. Fitts, Paul M. “The Information Capacity of the Human Motor System in Controlling the Amplitude of Movement.” Journal of Experimental Psychology 47 (1954): 381-391. 5. Gustafsson, Ewa, and Mats Hagberg. “Computer Mouse Use in Two Different Hand Positions: Exposure, Comfort, Exertion and Productivity.” Applied Ergonomics 34 (2003): 107-113. 6. Hedge, Alan, Timothy M. Muss, and Marisol Barrero. Comparative Study of Two Computer Mouse Designs. Department of Design and Environmental Analysis. Ithaca, NY: Cornell University, 1999. 7. Keir, Peter J., Joel M. Bach, and David Rempel. “Effects of Computer Mouse Design and Task on Carpal Tunnel Pressure.” Ergonomics 42 (1999): 1350-1360. 8. MacKenzie, I. S., Sellen, A., and Buxton, W. A comparison of input devices in elemental pointing and dragging tasks, Proceedings of the ACM Conference on Human Factors in Computing Systems-CHI’ 91. New York: ACM. 1991. 161–166. 9. Zipp, P., E. Haider, N. Halpern, and W. Rohmert. “Keyboard design through physiological strain measurements.” Applied Ergonomics 14 (1983): 117-122.
The Quill: Ergonomic and Usability Analysis and Evaluation
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APPE
ND IX A
Pre-Test Survey Subject #: ______________ 1.)
Are you left handed or right handed?
2.) What is type of input device do you currently prefer to use (touch pad, trackball, mouse etc.)?
3.) What type of input device do you use the most often? 4.) Please rate your self judged skill level at using the above mentioned computer input device. (1 being a novice and 5 being an expert) 5.) Of the four input devices being tested (WOW, Perific, Quill and Switch) which one looks the most appealing to you? Why?
expert). 7.) How many hours, on average, do you spend playing computer games per week? 8.) How many hours, on average, do you use a computer input device per week?
9.) Have you ever experienced discomfort associated from using an input device? If so describe.
10.) Please trace your hand on the back of this paper (the hand you use for inputting)
6.) How would you describe your level of experience with computer games? (1 being a novice and 5 being an 22
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APPENDIX B
Post-Test Survey
The Quill: Ergonomic and Usability Analysis and Evaluation
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APPE
ND IX C
Tables Corresponding with Graphs of Posture and Performance(figures 13-15)
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Spring 2008
APPENDIX C
The Quill: Ergonomic and Usability Analysis and Evaluation
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APPE
ND IX D
Paired Samples Statistics Performance:
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Spring 2008
APPENDIX D
Paired Samples Statistics Extension and Flexion:
The Quill: Ergonomic and Usability Analysis and Evaluation
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APPE
ND IX D
Paired Samples Statistics Radial and Ulnar Deviation
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Spring 2008
BLOOPERS
Some people find it difficult to figure out how to use the Quill:
Is it a phone?
An Iron?
The Quill: Ergonomic and Usability Analysis and Evaluation
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BLOO PER
S
Wait! The mouse buttons are in the wrong place...why isn’t this working? 30
DEA 470: Applied Ergonomic Methods
Spring 2008
BLOOPERS
It is called the “Quill”...why can’t it write!?!? The Quill: Ergonomic and Usability Analysis and Evaluation
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BLOO PER
S
Why aren’t you moving!?!? 32
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Spring 2008
The End The Quill: Ergonomic and Usability Analysis and Evaluation
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