Heidi Koester - Academia.edu (original) (raw)
Papers by Heidi Koester
Disability & Rehabilitation: Assistive Technology, 2007
We are developing a software system called IDA (Input Device Agent), whose goal is to optimally c... more We are developing a software system called IDA (Input Device Agent), whose goal is to optimally configure input devices for people with physical impairments. This study assessed IDA's ability to recommend three keyboard parameters in response to measurements of typing performance: repeat rate, repeat delay, and use of StickyKeys. Twelve typists with physical impairments participated. The study employed a repeated measures design. Each participant typed six sentences in each of four keyboard conditions: default settings, IDA-recommended repeat settings, StickyKeys On, and a repeat of default settings. Two participants had significant problems with inadvertent key repeats, when using the default repeat settings. For those two participants, use of the IDA-recommended repeat settings reduced the number of repeated characters by 96% and significantly improved text entry rate and typing accuracy. IDA recommended StickyKeys for six participants, each of whom had at least one problem related to modifying keys without StickyKeys. Use of StickyKeys for these individuals eliminated their modifier-related errors and significantly improved typing speed. IDA did not recommend StickyKeys for the six participants who demonstrated no need for it. The results indicate that IDA can provide useful assistance with repeat settings and StickyKeys.
Proceedings of the 7th international ACM SIGACCESS conference on Computers and accessibility - Assets '05, 2005
IEEE Transactions on Rehabilitation Engineering, 1994
This study analyzes user performance of text entry tasks with word prediction by applying modelin... more This study analyzes user performance of text entry tasks with word prediction by applying modeling techniques developed in the field of human-computer interaction. Fourteen subjects transcribed text with and without a word prediction feature for seven test sessions. Eight subjects were able-bodied and used mouthstick typing, while six subjects bad high-level spinal cord injuries and used their usual method of
The journal of spinal cord medicine, 2013
This study describes research behind two software wizards that help users with physical impairmen... more This study describes research behind two software wizards that help users with physical impairments adjust their keyboard and mouse settings to meet their specific needs. The Keyboard Wizard and Pointing Wizard programs help ensure that keyboard and pointing devices are properly configured for an individual, and reconfigured as the user's needs change. We summarize four effectiveness studies and six usability studies. Studies involved participants whose physical impairments affect their ability to use a keyboard and mouse. Effectiveness studies used an A-B-A design, with condition A using default Windows settings and condition B using wizard-recommended settings. Primary data were performance metrics for text entry and target acquisition. Usability studies asked participants to run through each wizard, with no outside guidance. Primary data were completion time, errors made, and user feedback. The wizards were effective at recommending new settings for users who needed them and ...
Journal of rehabilitation research and development, 2014
Single-switch scanning is a technique used by some individuals for spoken and/or written communic... more Single-switch scanning is a technique used by some individuals for spoken and/or written communication. We developed a method for adjusting the settings in a single-switch scanning interface to increase a user's text entry rate (TER). We evaluated that method with nine individuals who use single-switch scanning to communicate. Text entry rates improved by an average of 120% (p = 0.003). All nine subjects increased their TER by at least 40%, and five of the nine increased their TER by over 100%. At baseline, TER averaged 1.42 words per minute (wpm), ranging from 0.28 to 2.92 wpm. With the revised settings, TER averaged 2.72 wpm and ranged from 1.12 to 6.51 wpm.
We are working toward ways of optimally selecting and configuring input devices for people with p... more We are working toward ways of optimally selecting and configuring input devices for people with physical impairments. This exploratory study examined the effect of the following five factors on user pointing performance: (1) Gain setting; (2) Enhance Pointer Precision (EPP) setting; (3) Target size; (4) Target distance; and (5) Input device. For this group of 17 subjects, a lower gain combined with EPP On provided significantly better performance, although the gain effect was more variable across subjects. The type of input device used had the largest effect on pointing performance. BACKGROUND An important part of computer access interventions is appropriately choosing and configuring the user's pointing device. There are many pointing devices to choose from, ranging from "standard" mice to trackballs to head controls. Once a given pointing device is selected, tuning it to the user's strengths and limitations may yield significant performance and comfort benefits...
Fourteen individuals with various motor impairments performed a series of text entry exercises. P... more Fourteen individuals with various motor impairments performed a series of text entry exercises. Performance measures were collected which indicate overall performance (speed and error rate) and classification of errors. Such performance metrics could be useful in assessing the computer access skills of clients, and recommending software, hardware, or training interventions. BACKGROUND People with disabilities may have difficulty performing text entry tasks using a computer keyboard. The specific types of difficulty will vary depending on the person's intrinsic abilities, the input device being used, and the task. In order to understand and remediate the difficulties faced by a particular individual, it is desirable to quantify performance and classify errors. This aids in comparing performance over time or between input devices; evaluating the success of an intervention; or communicating the client's need for an intervention. General measures of typing performance include ...
Assistive Technology, 2007
Investigators have discovered that the ratio between a user&a... more Investigators have discovered that the ratio between a user's reaction time and an appropriate scan rate for that user is approximately .65, which we refer to as "the .65 rule." As part of a larger effort to develop software that automatically adapts the configuration of switch access software, data were collected comparing subject performance with a scan rate chosen using the .65 rule and a scan rate chosen by the user. Analysis of the data indicates that for many people, the .65 rule produces a scan rate that is approximately the same as the average switch press time plus 2 standard deviations. Further analysis demonstrates a relationship between the coefficient of variation (the standard deviation divided by the mean) and error rate. If accurate information is available about the mean, standard deviation, and distribution of a client's switch press time, a scan rate can be chosen that will yield a specific error level. If a rigorous statistical approach is impractical, the .65 rule will generally yield a usable scan rate based on mean press time alone.
This issue begins the 4th volume of ACM Transactions on Accessible Computing. The EiCs would like... more This issue begins the 4th volume of ACM Transactions on Accessible Computing. The EiCs would like to acknowledge the many people who contributed to Volumes 2 and 3 by their participation in the peer review process. In addition to the Editorial Board, the following people lent their time and expertise to the journal. ... Krzysztof Gajos Gregory Gay Dimitris Grammenos Peter Gregor Jon Gunderson Joshua Hailpern Gillian Hayes Shawn Henry Jesse Hoey Richard Kennaway Alasdair King Walter Kintsch Todd Kloots Heidi Koester Ravi Kuber Patrick Langdon ...
User-centered development of the Compass software for assessing computer input skills continues. ... more User-centered development of the Compass software for assessing computer input skills continues. This paper describes how we gather information about user requirements and evaluate system usability. These activities help to ensure that Compass will meet the needs of its users. Background We are developing software, called Compass, which allows an evaluator to assess an individual's computer input skills. This assessment
Disability & Rehabilitation: Assistive Technology, 2007
We are developing a software system called IDA (Input Device Agent), whose goal is to optimally c... more We are developing a software system called IDA (Input Device Agent), whose goal is to optimally configure input devices for people with physical impairments. This study assessed IDA's ability to recommend three keyboard parameters in response to measurements of typing performance: repeat rate, repeat delay, and use of StickyKeys. Twelve typists with physical impairments participated. The study employed a repeated measures design. Each participant typed six sentences in each of four keyboard conditions: default settings, IDA-recommended repeat settings, StickyKeys On, and a repeat of default settings. Two participants had significant problems with inadvertent key repeats, when using the default repeat settings. For those two participants, use of the IDA-recommended repeat settings reduced the number of repeated characters by 96% and significantly improved text entry rate and typing accuracy. IDA recommended StickyKeys for six participants, each of whom had at least one problem related to modifying keys without StickyKeys. Use of StickyKeys for these individuals eliminated their modifier-related errors and significantly improved typing speed. IDA did not recommend StickyKeys for the six participants who demonstrated no need for it. The results indicate that IDA can provide useful assistance with repeat settings and StickyKeys.
Proceedings of the 7th international ACM SIGACCESS conference on Computers and accessibility - Assets '05, 2005
IEEE Transactions on Rehabilitation Engineering, 1994
This study analyzes user performance of text entry tasks with word prediction by applying modelin... more This study analyzes user performance of text entry tasks with word prediction by applying modeling techniques developed in the field of human-computer interaction. Fourteen subjects transcribed text with and without a word prediction feature for seven test sessions. Eight subjects were able-bodied and used mouthstick typing, while six subjects bad high-level spinal cord injuries and used their usual method of
The journal of spinal cord medicine, 2013
This study describes research behind two software wizards that help users with physical impairmen... more This study describes research behind two software wizards that help users with physical impairments adjust their keyboard and mouse settings to meet their specific needs. The Keyboard Wizard and Pointing Wizard programs help ensure that keyboard and pointing devices are properly configured for an individual, and reconfigured as the user's needs change. We summarize four effectiveness studies and six usability studies. Studies involved participants whose physical impairments affect their ability to use a keyboard and mouse. Effectiveness studies used an A-B-A design, with condition A using default Windows settings and condition B using wizard-recommended settings. Primary data were performance metrics for text entry and target acquisition. Usability studies asked participants to run through each wizard, with no outside guidance. Primary data were completion time, errors made, and user feedback. The wizards were effective at recommending new settings for users who needed them and ...
Journal of rehabilitation research and development, 2014
Single-switch scanning is a technique used by some individuals for spoken and/or written communic... more Single-switch scanning is a technique used by some individuals for spoken and/or written communication. We developed a method for adjusting the settings in a single-switch scanning interface to increase a user's text entry rate (TER). We evaluated that method with nine individuals who use single-switch scanning to communicate. Text entry rates improved by an average of 120% (p = 0.003). All nine subjects increased their TER by at least 40%, and five of the nine increased their TER by over 100%. At baseline, TER averaged 1.42 words per minute (wpm), ranging from 0.28 to 2.92 wpm. With the revised settings, TER averaged 2.72 wpm and ranged from 1.12 to 6.51 wpm.
We are working toward ways of optimally selecting and configuring input devices for people with p... more We are working toward ways of optimally selecting and configuring input devices for people with physical impairments. This exploratory study examined the effect of the following five factors on user pointing performance: (1) Gain setting; (2) Enhance Pointer Precision (EPP) setting; (3) Target size; (4) Target distance; and (5) Input device. For this group of 17 subjects, a lower gain combined with EPP On provided significantly better performance, although the gain effect was more variable across subjects. The type of input device used had the largest effect on pointing performance. BACKGROUND An important part of computer access interventions is appropriately choosing and configuring the user's pointing device. There are many pointing devices to choose from, ranging from "standard" mice to trackballs to head controls. Once a given pointing device is selected, tuning it to the user's strengths and limitations may yield significant performance and comfort benefits...
Fourteen individuals with various motor impairments performed a series of text entry exercises. P... more Fourteen individuals with various motor impairments performed a series of text entry exercises. Performance measures were collected which indicate overall performance (speed and error rate) and classification of errors. Such performance metrics could be useful in assessing the computer access skills of clients, and recommending software, hardware, or training interventions. BACKGROUND People with disabilities may have difficulty performing text entry tasks using a computer keyboard. The specific types of difficulty will vary depending on the person's intrinsic abilities, the input device being used, and the task. In order to understand and remediate the difficulties faced by a particular individual, it is desirable to quantify performance and classify errors. This aids in comparing performance over time or between input devices; evaluating the success of an intervention; or communicating the client's need for an intervention. General measures of typing performance include ...
Assistive Technology, 2007
Investigators have discovered that the ratio between a user&a... more Investigators have discovered that the ratio between a user's reaction time and an appropriate scan rate for that user is approximately .65, which we refer to as "the .65 rule." As part of a larger effort to develop software that automatically adapts the configuration of switch access software, data were collected comparing subject performance with a scan rate chosen using the .65 rule and a scan rate chosen by the user. Analysis of the data indicates that for many people, the .65 rule produces a scan rate that is approximately the same as the average switch press time plus 2 standard deviations. Further analysis demonstrates a relationship between the coefficient of variation (the standard deviation divided by the mean) and error rate. If accurate information is available about the mean, standard deviation, and distribution of a client's switch press time, a scan rate can be chosen that will yield a specific error level. If a rigorous statistical approach is impractical, the .65 rule will generally yield a usable scan rate based on mean press time alone.
This issue begins the 4th volume of ACM Transactions on Accessible Computing. The EiCs would like... more This issue begins the 4th volume of ACM Transactions on Accessible Computing. The EiCs would like to acknowledge the many people who contributed to Volumes 2 and 3 by their participation in the peer review process. In addition to the Editorial Board, the following people lent their time and expertise to the journal. ... Krzysztof Gajos Gregory Gay Dimitris Grammenos Peter Gregor Jon Gunderson Joshua Hailpern Gillian Hayes Shawn Henry Jesse Hoey Richard Kennaway Alasdair King Walter Kintsch Todd Kloots Heidi Koester Ravi Kuber Patrick Langdon ...
User-centered development of the Compass software for assessing computer input skills continues. ... more User-centered development of the Compass software for assessing computer input skills continues. This paper describes how we gather information about user requirements and evaluate system usability. These activities help to ensure that Compass will meet the needs of its users. Background We are developing software, called Compass, which allows an evaluator to assess an individual's computer input skills. This assessment