Effectiveness of personal letters to healthcare professionals in changing professional behaviours: a systematic review protocol

Letters are regularly sent by healthcare organisations to healthcare professionals (HCPs) to encourage them to take action, change practice or implement guidance (e.g. reduce prescribing of antibiotics [1] and sedative hypnotics [2], and raise performance of mental health clinicians [3]). Letters are inexpensive, usually personalised and have wide reach [1]. Letter is commonly defined as ‘a written, typed, or printed communication, sent in an envelope by post or messenger’ [4‐6]. In addition, emails are usually defined as ‘written messages distributed by electronic means via a network’ [4].

Letters are promising in delivering behaviour change, especially when utilising particular behaviour change techniques (BCTs) boost the anticipated changes in behaviour. For example, Hallsworth [1] found that a letter containing a social norm message sent to general practitioners (GPs) notifying them that their practice is prescribing antibiotics at a higher rate than 80% of the practices in their local area reduced the prescribing rate compared to GPs who did not receive a letter. This study also revealed that a message from a high-profile sender (known as messenger effect) substantially reduced antibiotic prescribing at low cost and at national scale.

Whether letters are an effective tool in delivering a change in HCP behaviour is currently uncertain. The content of an intervention can be described through the use of BCTs which can be helpful in showing which particular techniques may contribute to intervention effectiveness. BCTs are the discrete and definable components of the given interventions that on their own have the potential to change behaviour. BCTs are observable and replicable and can be used alone or in combination with other BCTs [7]. A BCT is an ‘active ingredient’ such as self-monitoring of behaviour (e.g. keeping a daily diary of food consumption) [8]. Effective BCTs have been identified for interventions to increase physical activity and healthy eating and to support smoking cessation, safe drinking, prevention of sexually transmitted infections and changing professional behaviour [7]. However, there is currently no evidence about which BCTs [7] are used in letters, and how they might contribute to behaviour change.

Other approaches such as the MINDSPACE framework [9] could also identify and optimise the effects of letters to promote behaviour change. The MINDSPACE framework consists of nine evidence-based principles of behaviour change—messenger, incentives, norms, defaults, salience, priming, affect, commitment and ego—is becoming widely used within the policymaking community to improve the effectiveness of existing and new behaviour change policies [9, 10]. Likewise, there are a range of approaches to enhance behaviour change responses to letters, such as adding additional materials (e.g. a leaflet) or follow-up phone calls or text messages which might help boosting effects [1].

Despite the impact shown by selective studies for letters to be an effective tool in changing HCPs’ behaviours, to date, there has not been a comprehensive review to assess their potential in the context of population health. To address this research gap, we will conduct a systematic review that will identify what information and behaviour change techniques within letters that have the potential to optimise the effect on the behaviour of healthcare professionals.

The aim of this research is to conduct a systematic review of RCTs evaluating interventions that include letters sent to HCPs to alter their professional behaviour and to identify lessons for improved letter design leading to behavioural compliance.

Research questions:

This protocol has been registered within PROSPERO (number CRD42020167674) [11] and is being reported in accordance with the reporting guidance provided in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) statement [12, 13] (see checklist in Additional file 1). The systematic review will be reported following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement [14, 15].

A comprehensive literature search will be conducted in five electronic databases (from inception onwards): Medline, EMBASE, PsycINFO, Cochrane Library and CINAHL. We will conduct supplementary searches in Google Scholar, hand search relevant journals, and conduct backward and forward citation searching of included studies and relevant reviews. To identify additional grey literature not (yet) published in peer reviewed journals, we will contact partners (e.g. UK government departments such as Department of Health and Social Care (DHSC); agencies and public bodies such as Public Health England; behavioural science units such as the Behavioural Insights Team). The titles and abstracts retrieved by electronic searching will be downloaded to the reference management database EndNote.

A search strategy (see draft search in Additional file 2) following PICOS (population, intervention, comparison, outcome and study design) will be written for one database and then translated, using appropriate syntax and Medical Subject Headings (MeSH) terms for other databases [16, 17]. The PICOS process facilitates a more evidence-based approach to literature searching and helps to rapidly and accurately locate the best available scientific information, avoiding unnecessary searching [17].

This knowledge synthesis can serve as a guide for effective interventions to support providers and health authorities with advice on how to formulate the communication, what information and BCTs to include in order to optimise the potential effect of letters on the behaviour of the receivers (HCPs). Drawing on the findings, we will develop a guide to help staff optimise communications with HCPs. Reaching people with a message is one thing, influencing and changing their behaviour is another. Our behavioural science review will provide tried and tested methods that help us to design communications that more effectively influence the decisions HCPs make. This guide will include a checklist that details step by step instructions on how to design, develop and test behaviourally informed communications. It will include tips, techniques and examples of how the methods outlined have been used successfully around the globe in recent years. We will try to keep the guide as simple and accessible as possible. It is expected to help quickly learn about the theory, steps and techniques that can be applied to design more effective communications. Whether we want our recipients to start, stop or change a behaviour, following the checklist will help influencers to get the response they want. In particular, the review is hoped to inform the development of the multi-step checklist, which will include sections such as Receiver, Action, Sender, Channel, Techniques. In particular:

▶ Receiver: Who is the target audience? This step includes also finding opportunities for segmenting the target audience—i.e. grouping HCPs together by tendencies and characteristics so one can tailor the message to suit the characteristics of each different group.

▶ Action: What is the desired response? This step involves clearly defining the behavioural response required by the recipient(s) of the communication.

▶ Sender: Who is the sender of the letter? The receiver may respond differently depending on who is the messenger (e.g. central government, local authority, senior manager, regulator, clinical/professional body, nongovernmental organisation, and private company).

▶ Channel: What is the best mode of letter delivery (e.g. post, email, sms, in person) to maximise engagement for the selected Recipient and Effect?

▶ Techniques: Which BCTs can be used to design the communications for the selected Recipient, Effect, and Channel? Whilst techniques come in many different forms, we will list the ones that have proven to be particularly effective and useful when designing communications. For example, people are more likely to respond when they feel they are being addressed as individuals and not just a ‘number’. Also, does the letter grab and hold the reader’s attention? Is the language simple, clear and easy to understand? Is there a clear call to action (i.e. can the reader understand what is being asked of them and by when within the first few lines of the document)? Does it use the right tone of voice?

The behavioural analysis, which will be carried out using the Behaviour Change Wheel framework, will identify the key behaviours and, importantly, drivers for behaviours that may be amenable to change. The review will inform the development of a multi-step checklist, which will include sections such as Receiver, Action, Sender, Channel, Techniques, giving important insights and practical applications for policymakers, health insurers, and health systems. The inclusion of grey literature will broaden this study in terms of included information. Limitations of this review include the exclusion of papers reported in languages other than English. However, as the abstracts of these papers are usually written in English, screening will be implemented and a list of the references seemed to fulfil the inclusion criteria will be provided in appendix.

We will base our conclusions on findings from the narrative synthesis of included studies for this review. Health policy makers across government will benefit from being able to increase compliance in clinical settings by applying theories of behaviour to the design of policy communications, especially considering that letters are commonly used by health systems to influence HCPs.

There is growing evidence that BCTs can positively influence behaviours in a range of clinical situations. However, it remains unclear what BCTs have been most effective and how physicians experienced intervention letters (e.g. as helpful feedback or as a scare tactic). Ultimately, this kind of multicomponent intervention may have been the most effective approach considering that the low cost of the letter means that even a relatively small effect size could be cost-effective. These are important insights for policymakers, health insurers and health systems as they jointly pursue efforts to improve the value of care.