• 5.5 million outpatient appointments missed in England
  • Text saying missed appointment costs £160 could cut this number 
  • Trials found it cut 400,000 missed appointments a year
  • The texts would save the NHS £64 million a year

As many as 400,000 missed hospital appointments a year could be prevented simply by using well-worded warning texts, potentially saving the NHS £64 million.

A study based on one NHS Trust practice found ‘Did Not Attend’ (DNA) rates could be reduced by 5,800 - or as much as 28,900 if the Trust had a record of every patient’s mobile number - simply by making reference to the £160 cost the NHS incurs from each missed appointment in the text.

And assuming the NHS has just 20 per cent of patients’ mobile numbers it would reduce DNAs by 400,000, potentially saving the taxpayer an estimated £64 million.

Healthcare providers are increasingly using SMS reminders to reduce DNA rates with statistics showing in 2012-13 around 5.5 million NHS outpatient appointments were missed in England (9.3 per cent of the total). A recent estimate claims missed first outpatient appointments cost the NHS up to £225 million in 2012-13.

The research Stating Appointment Costs in SMS Reminders Reduces Missed Hospital Appointments: Findings from Two Randomised Controlled Trials by Ivo Vlaev, of Warwick Business School, Michael Hallsworth, Michael Sanders and Anna Sallis, of the Behavioural Insights Team, Dominic King and Ara Darzi, of Imperial College London, and Dan Berry, of the UK’s Department of Health, is the first to show evidence of the impact of the content in texts sent to patients.

Professor Vlaev said: “Moving from the existing text reminder to the more effective message emphasising the cost of missing an appointment would result in 5,800 fewer missed appointments per year at the NHS Trust in question, at no additional cost.

“On the same basis, full phone record coverage could result in 28,900 fewer missed appointments for the Trust annually.

“These results show that the wording of SMS reminders significantly affects the extent to which patients miss, attend or cancel outpatient appointments.

“Moreover, the results show that presenting the specific tariff cost of the appointment produces a DNA rate that is approximately three per cent lower than for other messages, a result that we replicated across two trials. Telling a patient the cost their missed appointment has on the NHS therefore genuinely persuades some to reconsider.”

The research involved two trials analysing outpatients with a valid mobile telephone number and an appointment. The first involved 10,111 patients between November 2013 and January 2014 and the second, between March and May 2014, was tested on 9,848 participants. They were randomly sent one of four reminder messages, which were issued five days in advance.

These outpatients were one of five specialities: rheumatology, ophthalmology, gastroenterology, neurology, and cardiology. These specialities were chosen because they were not currently the subject of any other initiatives to reduce DNAs, apart from the SMS reminders already in use.

In the first trial, a message including the cost of a missed appointment to the health system produced a DNA rate of 8.4 per cent, compared to 11.1 per cent for the existing message.

Message Wording DNA Percentage
Existing message (control) Appt at [clinic] on [date] at [time]. To cancel or rearrange call the number on your appointment letter 11.1%
Easy Call Appt at [clinic] on [date] at [time]. To cancel or rearrange call 02077673200 9.8%
Social Norms We are expecting you at [clinic] on [date] at [time]. 9 out of 10 people attend. Call 02077673200 if you need to cancel or rearrange 10.0%
Specific Costs We are expecting you at [clinic] on [date] at [time]. Not attending costs NHS £160 aprox. Call 02077673200 if you need to cancel or rearrange 8.4%

The second trial replicated this effect with a DNA rate of 8.2 per cent, but also found that expressing the cost implications in general terms without mentioning the exact amount was significantly less effective with a DNA rate of 9.9 per cent. 

Message Wording DNA Percentage
Specific Costs (control) We are expecting you at [clinic] on [date] at [time]. Not attending costs NHS £160 aprox. Call 02077673200 if you need to cancel or rearrange 8.2%
General Costs We are expecting you at [clinic] on [date] at [time]. Not attending wastes NHS money. Call 02077673200 if you need to cancel or rearrange 9.9%
Empathy We are expecting you at [clinic] on [date] at [time]. Please be fair to others waiting and call 02077673200 if you need to cancel or rearrange. 10.7%
Recording We are expecting you at [clinic] on [date] at [time]. Please attend or call 02077673200 to cancel/rearrange, or we will record as a missed appt. 9.6%

“In crude terms, this comparison suggests that the content of SMS reminders may constitute a large part of their overall effect. The more general implication is that health system performance improvements do not depend on technical solutions alone,” added Professor Vlaev.

“The fact that there were no significant differences between the ‘control’ and ‘social norms’ messages means we can be confident that the effect of the ‘specific costs’ message is not being driven by the ‘we are expecting you’ message framing, or the presence of the telephone number."


Ivo Vlaev is Professor of Behavioural Science and teaches Mobilising Resources and Incentives for Healthcare Innovation on the MSc Strategic Leadership & Innovation in Healthcare.

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