This open source protocol and toolkit could inspire the novice to start their studies in keyboard designs, optimize the user experience, and improve the revenue of input method at the companies. This protocol provides a systematic method to evaluate the keyboard design more precisely on smartphones. Various highly accepted indicators, and the new special indicators are involved in this protocol.
A novice researcher may be confused about choosing appropriate evaluating indicators, and experimental programming. We provide subjective indicators, objective indicators, and Python script to reference. Demonstrating the procedure will be Yincheng Wang and Ke Wang, students from my laboratory.
Begin by reading the consent form to the participant regarding the experimental procedure, and their discretion for participation, including the experiment procedure task, and whether they will encounter any mental or physical injuries. If the participant agrees to participate, ask them to sign the informed consent form. Measure the hand size of every participant to eliminate the effect of hand size difference, and to provide repeatable data for future research.
Collect demographic data, such as age, gender, precise input experience, and occupation of the participants. Disinfect all devices and clean the body parts of the participant that will touch the devices. Ask participants to wash their hands and clean their smartphone screens.
Ask the participants to wear portable wireless physiological detectors, or a motion capture system. Then ask them to put the portable wireless physiological detection wristband on their non-dominant hand to record a galvanic skin response, and heart rate, without noise interference. To collect precise body and finger movement place passive markers of the motion capture system on the fingernails, the proximal phalanx of the finger, cervical vertebrae from C3 to C5, and arm.
Stick wireless electrodes to the skin of the arms and forearms to detect the electromyographic activity. Then calibrate all devices. Allow the participant to complete the training task, which is used to improve their familiarity with the input tasks and keyboards.
Only allow participants whose accuracy reaches 80%or more in 150 seconds to enter the formal trials. Let participants complete formal trials under all experimental conditions described in the text manuscript, having them complete the input task in a random or a balanced order. Each pair, word, or sentence represents a trial, and different experimental designs produce different experimental conditions.
After each condition, ask the participants to complete all the questionnaires at random to obtain subjective feedback. And allow them to rest for one minute. Express appreciation to participants with monetary or material rewards.
This study was used to evaluate two keyboard layouts, namely the curved QWERTY and traditional QWERTY, with different sizes of buttons. The statistical analysis of the input performance, subjective feedback, and fitted ellipse of each button is shown here. The transition time between two keys with a small button size was significantly longer than that between keys with a large button size in the curved QWERTY.
The word error rate of the traditional QWERTY was significantly lower than that of the curved QWERTY. The main effect of keyboard layout is significant in intent to use"and subjective workload, showing that participants perceive less subjective workload and are more likely to use the curved QWERTY when compared to the traditional QWERTY. The six dimensions of the subjective workload are shown here.
In the area of the fitted ellipse, the interaction between keyboard layout and button size is significant, showing that for both small and large button size, the area of the traditional QWERTY is larger than that of the curved QWERTY. For both keyboard layouts, the area of the small button is smaller than that of the large button. In the offset of the fitted ellipse, the interaction between keyboard layout and button size is only significant in the offset in the Y direction.
In the curved QWERTY, the offset in the Y direction of the small button is significantly shorter than that of the big button. Remember to keep the screen and participant's hand clean before experiment. Training tasks and balanced experimental conditions help to avoid the practice effect and other confounding factors.
This protocol can be adopted in the evaluation of keyboard design in the touch screen of other smart devices, such as a wearable smart watches, tablet PC, and virtual reality devices.
