Seite - 67 - in Applied Interdisciplinary Theory in Health Informatics - Knowledge Base for Practitioners

experience, and voluntariness of use moderate the impact of the key variables on usage intention and behavior. The original UTAUT validation study [2] found that UTAUT was able to explain 70% of the variance of Behavioral Intention, which indicates high predictive power. Table 2 summarizes the basic definition of the variables used in UTAUT. Figure 2 shows the UTAUT model. The similarities to TAM are obvious when comparing both models. Table 2. Definitions of the variables used in UTAUT [2]. Performance Expectancy Degree to which an individual believes that using the system will help him or her to attain gains in job performance. Effort Expectancy Degree of ease associated with the use of the system. Social Influence Degree to which an individual perceives that important others believe he or she should use the new system. Facilitating Conditions Degree to which an individual believes that an organizational and technical infrastructure exists to support use of the system. Behavioral Intention to Use Measure of the strength of one’s intention to perform a specified behavior. Figure 2. Unified Theory of Acceptance and Use of Technology (UTAUT) [2]. A PubMed query on “Unified Theory of Acceptance and Use of Technology” retrieved 80 papers from 2008 onwards (search done on 7 June 2018), showing the popularity of UTAUT within health informatics research. 2. Usage of TAM and UTAUT in health informatics This section describes two use cases of health informatics interventions where TAM and UTAUT were applied. E.Ammenwerth /TechnologyAcceptanceModels inHealth Informatics: TAMandUTAUT 67