Plain English Summary
Background and study aims
Over 6 million hospital appointments are missed each year in the NHS, about 8.5% of the total number. Non-attendance results in wasted money and wasted doctors and nurses time, administrative problems and poor patient care. In 2008 it was estimated that missed outpatient appointments cost the NHS around £600 million a year. The aim of this study is to apply learning from a relatively new area of science, called behavioural economics, to see if the NHS can reduce the number of missed appointments. This can potentially save the NHS a lot of money and improve patient care. The research team thinks it can reduce missed appointments without spending any more money, simply by improving the text message reminders that hospitals often send to patients before their appointments. The study will compare four different text messages (current one and three new ones).
Who can participate
10,000 patients at clinics at Barts Hospital in London, who have agreed to receive text message reminders about their appointment.
What does the study involve?
The research team only sends text messages to patients who have already agreed with the hospital that the hospital can send them text message reminders. The research team does not access any part of a patients personal identifiable information, nor their clinical records.
Participants are randomly allocated one of four groups corresponding to four different messages:
1. Appt at <clinic> on <date> at <time>. To cancel or rearrange call the number on your appointment letter. (this is the current text message used at Barts Hospital).
2. Appt at <clinic> on <date> at <time>. To cancel or rearrange call 0207389471.
3. We are expecting you at <clinic> on <date> at <time>. Nine out of ten people attend. Please call 0207389471 if you need to cancel or rearrange.
4. We are expecting you at <clinic> on <date> at <time>. Not attending costs NHS £160 on average, so call 0207389471 if you need to cancel or rearrange.
What are the possible benefits and risks of participating?
The benefits of participating are that patients are more likely to attend a medical appointment that they, and their doctor, have agreed they should attend. This also reduces waste in the NHS. Interim results from the first part of the research suggest that all of the new messages being tested are better than the current message used.
The research team thinks there are minimal risks to patients; this has no impact on patient care, does not compel patients, nor seek to persuade them to do anything. Access to treatment and to the work of doctors and nurses is unaffected. The research team does not access a patients personally identifiable information; the research team only looks at the aggregated data.
Where is the study run from?
Barts Hospital in London, UK.
When is the study starting and how long is it expected to run for?
The study is expected to run from November 2013 to May 2014.
Who is funding the study?
Imperial College London and the Department of Health (UK).
Who is the main contact?
Mr Daniel Berry
Study to test the content of the most effective SMS reminder message to reduce missed appointments in hospital outpatient clinics: a between groups randomised controlled trial
This study is to test the content of the most effective SMS reminder message to reduce missed appointments in outpatient clinics.
A systematic review of telephone and SMS reminders found that they significantly improved attendance. A Cochrane Review on the topic found relatively little robust evidence so far, but that which does exist indicates that SMS reminders offer a flexible, effective, cost-effective means of increasing appointment attendance.
While many NHS organisations already use SMS reminders, we believe they can be made more effective by improving the messages they contain. However, there is currently no evidence for which text messages are most effective
We are collaborating with Barts Hospital to test different text message invites and reminders to reduce missed appointments.
These messages draw on the latest evidence fro the behavioural sciences of how message content can influence behaviour. For example, messages drawing on social norms, salient costs and benefits, and simplicity. We believe this is an opportunity for Barts Hospital and other hospitals to improve outcomes at little or no additional cost.
NHS Research Ethics Committee, 28/06/2013, ref: 13/NW/0508
Between groups randomised controlled trial
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
The study involves 10,000 patients at clinics at Barts Hospital who have agreed to receive text message reminders about their appointment. Patients are allocated to receive one of four different messages at random (randomised using the Mersenne twister method). The messages are as follows:
Control: Appt at <clinic> on <date> at <time>. To cancel or rearrange call the number on your appointment letter.
We propose to retain this current SMS message as a control while introducing the following variants
Trial arm A: Appt at <clinic> on <date> at <time>. To cancel or rearrange call 0207389471.
Reducing even apparently minor barriers to carrying out a behaviour can significantly increase the incidence of that behaviour. For example, a seminal study from the field of social psychology found that vaccination uptake was low even after education had been provided and broad intentions formed. However, uptake increased from 3% to 28% by simply providing a map and asking participants to think about an appointment time: these small 'channel factors' made a large difference (Leventhal, Singer, and Jones, 1965).
Similarly, it is likely that the process of having to locate the appointment letter reduces the effectiveness of the control message. We have been advised that it is possible to include the specific telephone number, and we would like to test the impact of doing so:
Trial arm B: We are expecting you at <clinic> on <date> at <time>. Nine out of ten people attend. Please call 0207389471 if you need to cancel or rearrange.
There is much evidence that even short messages based on social norms saying what other people do in the same situation - can have a significant effect on compliance (e.g. Hallsworth et al., 2013). Given that only around 10% of patients do not attend, there is a clear opportunity to leverage social norms:
Trial arm C: We are expecting you at <clinic> on <date> at <time>. Not attending costs NHS £160 on average, so call 0207389471 if you need to cancel or rearrange.
Given that people are exposed to a great amount of information every day, a message must be framed in a salient way to have the best chance of being effective (Dolan et al., 2010). The costs of missing an appointment are likely to be unknown to the patient. Alternatively, he/she may have some awareness of the 'opportunity cost' incurred by a missed appointment, but this is likely to be of very low salience (Frederick et al., 2009). Therefore, stating these costs in a salient way is likely to improve the effectiveness of the message. Costs vary, but we have established £160 as the average cost for the clinics we propose to work with at Barts.
Primary outcome measures
Number of patients who attend their outpatient appointment
Secondary outcome measures
Overall trial start date
Overall trial end date
Participant inclusion criteria
All patients over the age of 18 at five clinics at Barts Hospital who have already provided their mobile phone number to Barts Hospital, for the duration of the trial
Target number of participants
Participant exclusion criteria
All other patients
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Department of Health (UK)
Funding Body Type
Funding Body Subtype
Imperial College London (UK)
Funding Body Type
private sector organisation
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Results - basic reporting