This week’s launch of the ‘Wayfinder’ waiting time information service on the NHS App will give patients “disingenuous” and “misleading” information about how long they can expect to wait for care, senior figures close to the project have warned.

Briefing documents show the figure displayed to patients will be a mean average of wait times taken from the Waiting List Minimum Data Set and the My Planned Care site.

However, it was originally intended that the metric displayed would be the time waited by 92 per cent of relevant patients. This is more commonly known as the “nine out of 10” measure.

Mean waits are likely to be about “half the typical waiting time” measured under the nine out of 10 metric, according to waiting list experts.

Ahead of The Wayfinder service’s launch on Tuesday, NHS trusts and integrated care boards have been sent comprehensive information on how to publicise it, including a “lines to take” briefing in case of media inquiries. This mentions the use of an “average” time but does not provider any justification for this approach.

The guidance explains that patients will be “shown two data points: the date of their referral and the estimated month that their first treatment will take place. The waiting time shown is the (mean) average of all patients waiting within the speciality at the trust. Some patients will wait less time than the average and some patients will wait longer than the average waiting time.”

It recommends that trusts and GP practices “identify staff to advocate for the use of the NHS App”.

A senior source close to the project said the choice of mean times had been signed off by NHSE chief executive Amanda Pritchard, despite significant concerns from service leaders. They said the mean average metric would be providing patients with “disingenuous” information and added that the 92nd percentile metric would be a “far more realistic” measure “for a greater number of people”. They concluded that “using an average” would create false expectations “because in reality nobody will be seen in the amount of time it is saying on the app.”

Experts have previously criticised proposals to replace the 92nd percentile metric with an average waiting target during a similar debate around the “clinical review of standards”.

NHSE has said the new feature will improve patient experience by keeping them more informed and reassuring them that they are “in the system”.

The NHSE briefing documents claim the Wayfinder service, alongside other information provided by the app, could remove up to 20 per cent of existing phone calls to GPs by answering common queries.

When NHSE launched the “My Planned Care” service from which the waiting times is pulled in February 2022 they claimed it would “allow patients and their carers to access information ahead of their planned appointment, operation or treatment through the touch of a button”.

An NHSE spokesperson said: “This new feature has been designed to make it as easy as possible for patients to understand the average wait for their treatment before they receive their appointment details, and the NHS will continue to take on user feedback and iterate this feature to continually improve it.”