How social norms reduced missed hospital appointments by 31.7%

Intervention · Salud


Missed hospital appointments are a massive strain on resources and can lead to worsened health and financial outcomes. Researchers Martin, Bassi, and Dunbar-Rees tested three behavioral science interventions in two health centers in NHS Bedfordshire.1The first two interventions tackled “did not attends” (DNAs) by increasing patient participation in phone and in-person bookings, a process which is normally fully carried out by healthcare professionals. These interventions reduced DNAs by 3.5% and 18%, respectively. The third intervention combined the previous two, and additionally took advantage of social norms. By making it known how many people successfully make their appointment, this intervention utilized descriptive norms to minimize DNAs. In combination, the three interventions were able to reduce DNAs by 31.7%.

Rating = 4/5 (Effective; easy to implement; could be improved by testing the effect of social norms not in conjunction with other conditions)

How three behavioral science interventions affected “did not attends” (DNAs) in health centers
Asking participants to verbally repeat time and date of appointment during phone booking Decreased by 3.5% in the following month
Asking participants to write down time and date on appointment card  Decreased by 18%
Showing participants the number of patients who made their appointments (combined with the previous two conditions) Decreased by 31.7%

Key Concepts

Social norms: Collectively held beliefs about what kind of behavior is appropriate in a given situation.

Descriptive norms: A type of social norm that describes how most people actually behave in a given situation.2

The Problem

The burden of DNAs

Globally, approximately 23% of patients miss their clinical appointments.3 The impact of DNAs is immense, as it wastes the resources of healthcare professionals, prevents other patients from receiving care, and can lead to worse outcomes for the patient if their health deteriorates due to a lack of treatment. In the UK, approximately one in 20 general practice appointments are missed, causing a loss of over £216 million a year.4  Up to 84% of general practitioners (GPs) state that DNAs cause longer waiting times and skyrocket costs, make it more challenging to reach performance targets.1 

The causes of DNAs

Although there are many reasons DNAs occur, the researchers of the current intervention explain the most common reason is simple forgetfulness. Many attempts have been made to reduce the negative impacts of DNAs previously, with one option including overbooking clinics. Even though overbooking can help avoid wasting the time of healthcare professionals, the solution is suboptimal, due to the damage it can cause patients. For example, it risks increasing wait times. 

Previous solutions

The researchers pointed out that, although reminders of appointments have been helpful in healthcare settings previously, reminders aren’t always appropriate in the context of primary care, where appointments must often be attended within 24-48 hours. As a result, a common approach in such settings is to simply publish the number of DNAs for the public to see, which likely aims to induce guilt or highlight the issue. However, previous research has shown that invoking a descriptive norm in a way that highlights the frequency of unwanted behaviors can actually increase their incidence. 

Another solution previously proposed was introducing fines for missed appointments, however, fines are difficult to enforce and can introduce an additional burden to those who have fallen ill or have chronic illnesses.


The current intervention was inspired by the use of behavioral interventions to reduce DNAs in other industries, such as hospitality and restaurants. The experimenters wanted to see if simple behavioral interventions could similarly have a large impact on DNAs in health centers.

Intervention 1: Active commitments

In the first intervention, the experimenters tested if more active participation from patients in phone call bookings would reduce DNAs. Initially, the staff were told to make patients write down a 4-digit reference number. The hope was that the reference number, which was salient and new, would impact memory of the appointment along with the active participation. This prediction is reasonable, as salience attracts our attentional resources. Unfortunately, due mostly to staff non-compliance, this procedure didn’t work. To increase compliance, researchers proposed an easier intervention: staff would now ask if patients could verbally repeat back the date and time of the appointment.

Intervention 2: Written commitments

In the second intervention, which was conducted in nurse clinics, nurses were asked to make patients write down the time and date on an appointment card themselves. This intervention was inspired by research demonstrating that commitments to action can be strengthened by writing.

Intervention 3: Social norm communication

In this phase, the researchers wanted to test whether using descriptive messaging of the number of patients that do make their appointments would influence DNAs. They choose to replace signs that listed those who didn’t show up with signs that showed off the large numbers of people who did make it. They chose to test this intervention in conjunction with interventions one and two.

Results and Application

Intervention 1: Active commitments

In the first intervention, when staff were initially instructed to make patients write down an appointment verification number, the number of DNAs actually rose. The researchers quickly learned that the reason for this failure was that staff found it too difficult and time-consuming to comply with the intervention. Based on this feedback, the intervention was changed, now asking participants to repeat their appointment time and date. The staff readily agreed with this change, and DNAs were reduced by 3.5% in the following month.

Intervention 2: Written commitments

Making clients write down a time and date on their appointment card was even more successful. After the intervention, DNAs were down by 18% compared to the previous six-month average.

Intervention 3: Social norm communication

The final intervention, which combined the aforementioned strategies and communicated the desirable descriptive norm, resulted in a 31.7% reduction in DNAs compared to the previous year. When the researchers paused the intervention, DNAs spiked. When the intervention was reinstated, the following month saw a reduction of 29.6% in DNAs.

The EAST framework

The success of the intervention can be analyzed using the EAST framework. This framework was initially developed by the Behavior Insights Team for policymakers and emphasized that policies should be easy, attractive, social, and timely. These aspects all affected the intervention targeting DNAs:

  • Easy: The intervention only became successful at reducing DNAs after it was easy to implement for both the clinic clients and the staff.
  • Attractive: Although incentives for reducing DNAs are very significant in terms of saving financial resources and time for staff, clearly communicating the potential gains to staff and patients could have improved the intervention.
  • Social: The third part of the intervention, which used descriptive norms greatly reduced DNAs.
  • Timely: Considering time constraints worked in the favor of the intervention in nurse clinics. The researchers explained that previous strategies for reducing DNAs, such as reminders, would not be as appropriate in this context due to the short amount of time between booking and attendance. The current intervention improved on this by addressing the issue during booking times specifically.

Overall, the researchers concluded that behavioral interventions are successful in reducing DNAs and suggest similar interventions should be considered in other behavioral aspects of medicine. For example, they see the potential of similar interventions in promoting medication adherence and exercising. 

Public Policy Social norms could be utilized in ‘get-out-the-vote’ campaigns by telling eligible voters how many people in their age group or neighbourhood voted in the previous election
Health & Wellbeing Reminder techniques can extend to goals like regular exercise - i.e. apps that track movement and compare users in similar ranges
Development & Social Protection Organizations can use similar nudges to remind volunteers of their shifts - as they are not financially motivated, the risk of missing a shift may be more likely


  • It seems the researchers may not have considered how the behavioral interventions can inconvenience staff prior to launching intervention one. Future studies should conduct interviews with those who will execute interventions to ensure the design does not overburden staff.
  • It remains unclear whether the health centers continued to use the interventions upon completion of the study. Conducting long-term check-ups on health centers could help determine the sustainability of the interventions.
  • DNAs lead to an enormous loss of resources for the NHS that could be allocated to patients in need. The intervention addresses this problem and thus helps to ensure a more just and equitable distribution of welfare.

Does the intervention demonstrably improve the lives of those affected by it?
The intervention improves both the health and finances of patients, as well as the resource allocation of healthcare staff.
Does the intervention respect the privacy (including the privacy of identity) of those it affects?
Not applicable
Privacy concerns do not seem relevant as the study appears to only collect aggregate data regarding DNAs. 
Does the intervention have a plan to monitor the safety, effectiveness, and validity of the intervention?
Insufficient information
The experiment was safe and valid. Although each hospital can continue to use the interventions and measure DNAs, it was not clear whether this occurred after the experimenters concluded their research.

Does the intervention abide by a reasonable degree of consent?
In terms of patient consent, it does not appear necessary since only aggregate data regarding DNAs was collected.
Does the intervention respect the ability of those it affects to make their own decisions?
The intervention respects the ability of patients to make decisions.
Does the intervention increase the number of choices available to those it affects?
Room for improvement
It doesn’t appear that much choice availability was presented.

Does the intervention acknowledge the perspectives, interests, and preferences of everyone it affects, including traditionally marginalized groups?
Insufficient information
The intervention did not sufficiently address the preferences of hospital staff, however there is insufficient information to draw conclusions.
Are the participants diverse?
Insufficient information
Diversity of participants depends on diversity of patients in the health centers, which remains unspecified.
Does the intervention help ensure a just, equitable distribution of welfare?
DNAs lead to an enormous loss of resources for the NHS that could be allocated to patients in need. This intervention reduces this problem and thus helps to ensure a more just and equitable distribution of welfare.

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To learn more about normative influence in healthcare, read this interview with Dr. Patricia Cummings, which explains how normative influence amongst doctors can address the urgent public health threat of increasing antibiotic resistance. 


Two of the three interventions in this study focused on making participants more active in their appointment bookings. One reason that this type of strategy can work is due to an increase in one’s sense of commitment. Read this article to learn how to take advantage of precommitment to reach goals even greater than making your doctor’s appointments, including tackling gambling addiction.


  1. Martin, S. J., Bassi, S., & Dunbar-Rees, R. (2012). Commitments, norms and custard creams – a social influence approach to reducing did not attends (dnas). Journal of the Royal Society of Medicine, 105(3), 101–104.  
  2. American Psychological Association. (n.d.). APA Dictionary of Psychology. American Psychological Association.
  3. Dantas, L. F., Fleck, J. L., Cyrino Oliveira, F. L., & Hamacher, S. (2018). No-shows in appointment scheduling – a systematic literature review. Health Policy122(4), 412–421.
  4. NHS. (n.d.). Missed GP appointments costing NHS millions. NHS.
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