Development of a scale to assess the usability of government One-Stop Portals

One-stop portals (OSPs), websites that integrate government services and information in a single place, are used by millions of citizens in more than 90 countries. However, little is known about their usability. Four studies were conducted in this research to develop and validate a scale to assess the usability of OSPs, the Government Usability Measure (GUME). Study 1 investigated the reliability, construct validity, and dimensionality of a preliminary 60-item scale. Experts found the scale had good face validity, content validity and did not elicit socially desirable responses. Two factors, perceived usability (PU) and perceived information quality (PIQ) explained about 75% of the variance. The subscales were highly reliable. A refined 27-item scale was developed that maintained the reliability and dimensionality of the preliminary scale. Study 2 investigated the construct validity of the GUME in the domain of cultural institutions websites. A model based on the GUME factors was assessed using confirmatory factor analysis. Results supported the model fit, the reliability of its constructs, as well as its convergent, nomological and discriminant validity. Study 3 examined the sensitivity of the GUME to detect manipulations of PU and PIQ. Respondents evaluated two versions of an experimental OSP differing in their levels of PU and PIQ (i.e. good and poor). An effect was found with high power that supported the sensitivity of the GUME to detect real differences in PU and PIQ between OSP versions. Study 4 investigated the effect of service-clustering themes on PU and PIQ. Respondents conducted a task-based evaluation of three versions of an experimental OSP differing in their service-clustering theme (i.e. audiences, life-situations and topics). The study produced no differences in PU and PIQ between OSPs. Overall, the psychometric properties of the GUME were supported. The methodological, theoretical and practical implications of these findings are discussed in this thesis.