Psychometric Analysis of Scales for Usability Evaluation of Pointing Devices

Abstract

Usability evaluation involves measuring user performance (effectiveness and efficiency) and registering the user’s perception of satisfaction related aspects. The paper reports on a method for assessing the satisfaction component, in computer handheld pointing devices, through a series of ratings related to three dimensions: comfort (discomfort), ease of use (per task performed) and effort (gripping, pointing, clicking). Cronbach’s alpha is obtained as an estimate of the reliability of the assessment method made up of the multiple attribute evaluation of discomfort, ease of use and effort, based on Likert scales. Results revealed high values of internal consistency within each subjective dimension. Increased internal consistency would be obtained by removing the shoulder discomfort attribute from the discomfort evaluation questionnaire, and gripping and clicking attributes from the effort evaluation questionnaire. These divergences indicate that participants perceived these attributes as fundamentally different from the rest of the attributes within the evaluation dimensions.