Optimizing Weblinks Used in Digital Vaccination Invitations to Raise Trust and Booking Intention: Online Experiment 2

This study investigates how the design of web links in digital vaccination invitation emails affects recipient trust and their willingness to book an appointment. Researchers compare three different weblink formats: a control third-party link previously used by the NHS (\"accurx\"), and two experimental weblinks in which the original link is hidden: a shortened \"bit.ly\" link, and a text-embedded hyperlink. The study primarily tests whether the two experimental weblinks will be perceived as more trustworthy and increase booking intention compared to the control weblink. Furthermore, the study examines whether the experimental weblinks is perceived to be more fluent (easier to read) and improves participants\' ability to correctly identify the organisation (e.g., the NHS or a US pharmacy) that sent the hypothetical email. To test these effects, investigators will gather data from 600 participants from the United Kingdom and 600 from the United States. They will be randomly assigned to view one of the three hypothetical email versions. UK participants will see emails appearing to be from the NHS, while US participants will see emails from a fictitious pharmacy (Pharma-US). This research aims to provide evidence on how to design more effective and trustworthy digital health communications.