Fewer than half believed a real NHS booking link led to the NHS

October 2026 · Luca

On many clinic websites the Book button does not open a page of the clinic’s own site. It opens the booking software, on the software company’s address. I wanted to know whether anyone has measured what the address of a booking link does to the person about to click it. I found one recent study that comes close. It is about an email, not a website, and this article says what that changes.

What the study did

In August 2026 a team led by psychologists at the University of Essex published three randomized experiments in the Journal of Medical Internet Research.1 Adults living in the United Kingdom read an email inviting them to book a COVID-19 vaccine with the National Health Service, the NHS. The email was the same for everyone. Only the booking link changed, and who saw which link was decided at random by the survey software, double blind.

The starting point was a real link, one the NHS had used and people in the UK had already received: accurx.thirdparty.nhs.uk/r/aafwaczmd5. As the authors point out, the NHS part is squeezed between a reference to a third party and a string of letters and numbers. Against it, the experiments tested:

a clear address, vaccine-booking.nhs.uk;
a shortened address, bit.ly/3GtTL0c;
the link hidden behind words, book here.

569 people took part in the first experiment, 596 in the second and 1,993 in the third. They said how much they trusted the email, who they thought ran the website behind the link, and how likely they were to book through it.

What it found

63%of the people shown the real NHS link were unsure or unlikely to use it, 729 of 1,142
< halfof all participants believed the real link would take them to an NHS page

The clear address raised trust in the email in both experiments where it was tested. The link hidden behind “book here” raised it too. The bit.ly address did not: shorter, but no clearer about who was on the other end. The authors’ analysis points to the reason. What made the difference was whether people could tell who ran the website, and trust in turn went together with a higher intention to book.

The gain was not the same for everyone. Younger participants stayed as suspicious of the email with the clear link as with the real one, in the third and largest experiment.

The authors draw on the same idea as the article on links and buttons: information scent, the cues people read before they click to judge whether a path is worth following.2 The authors call the real link ambiguous and hard to read, which is why it gave little to go on even though it was genuine.

What this study does not show

It is an email, not a website. Someone who has already chosen a clinic and pressed its Book button is in a different position from someone deciding whether an email is a scam.
The invitation was hypothetical, and the study measured trust and intention to book, not bookings. The authors say so themselves and call for real tests.
It was a free vaccine from a national health service, not a paid treatment from a private clinic.
That trust goes together with intention to book is an association within the data, not a measured effect of the link on bookings.

The study was funded by a British Academy grant, and the authors declare no conflicts of interest. One of the eight authors works at the UK Health Security Agency.

What I take from this for a clinic

I found no study that measures what it costs a clinic to send its booking button to another company’s address. This is the closest evidence I found, and it is about an email.
People do read the address, and they look for who is behind it. In this study a real link from the national health service left most of the people who saw it unsure or unwilling to use it, and what mattered was whether they could tell whose website it was.
Words helped too. “Book here” did better than the raw address, if a little less than the clear one. On a website that is the button’s own label, and what the booking page shows when it opens.
So in an audit I check where the Book button lands, and whether that page says it belongs to the clinic: its name, its logo, the treatment the visitor was reading about. What I do not do is tell a clinic this costs it bookings. Nobody has measured that.

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Sources

Each source was opened and read before this page was written. The first was read in full; for the second only the abstract was available, and this is stated next to it.

Oakley, C. M., Sayer, H., Holford, D., Bruine de Bruin, W., Vallée-Tourangeau, G., Chadborn, T., Sirota, M., & Juanchich, M. (2026). Optimizing web links used in digital vaccination invitations to raise trust and booking intention: 3 online randomized controlled trials. Journal of Medical Internet Research, 28, e85480. doi.org/10.2196/85480 Design: three randomized, double blind online experiments with a hypothetical email, peer reviewed. 569, 596 and 1,993 adults living in the UK, recruited through Prolific and Qualtrics. Outcomes self-reported: trust, who runs the website, intention to book.
Pirolli, P., & Card, S. (1999). Information foraging. Psychological Review, 106(4), 643 to 675. doi.org/10.1037/0033-295X.106.4.643 Type: theory with a computational model, peer reviewed. Read at abstract level.