How do credibility and utility play in the user experience of health informatics services?

While the use of health informatics is increasing in health care, how it is improving health care and how users accept the services has been little studied, and due to increasing uncertainty, credibility has become a key determinant of health informatics adoption and diffusion. However, little is known about the underlying nature of user trust or how early-stage credibility influences later-stage behavior and experience. To enhance the explanatory power and make it more applicable to health consumers' behavioral intentions, expectation-confirmation theory was extended by adding antecedents and moderating variables from the theory of planned behavior. With health informatics services in place, this study investigates how credibility influence other user perceptions such as perceived utility and how these perceptions together determine user intentions and behaviors concerning health informatics at both the initial and later stages of use. Cross-sectional and longitudinal analysis of these attitudes and behaviors was carried out, and the results showed that perceived utility and credibility are critical at both the initial and later stages in user acceptance of health informatics services. Users' actual experiences modify their perceptions of utility and influence the confirmation of their initial expectations. These results have implications for the fundamental nature of credibility and perceived utility as well as their roles in the long-term sustainability of future health informatics services.