Chapter 2Developing a comprehensive list of behaviour change techniques (study 1)

Publication Details


Objectives: To develop an extensive, consensually agreed taxonomy of BCTs used in BCIs.

Methods: In a Delphi-type exercise, 14 experts rated labels and definitions of 124 BCTs from six published classification systems.20,23,27,29,33,36 The resulting list was refined based on the feedback from group discussions of 16 members of the International Advisory Board (IAB).

Results: This resulting BCTTv1 comprised 93 distinct, non-redundant and non-overlapping BCTs.

Conclusions: BCTTv1 offers a step change in methods for specifying interventions using shared concepts and language. When sufficient data have been collected about its implementation and an international, interdisciplinary consortium established, v1 will be reviewed and v2 released as and when the need is judged by consensus.


Literature reviews find that even essential elements of interventions are frequently omitted from intervention descriptions; an analysis of trials and reviews found that 67% of pharmacological intervention descriptions were adequate, compared with only 29% of non-pharmacological intervention descriptions.41 While this occurs in descriptions of all types of intervention, it is an even more common problem in BCIs. Titles and abstracts of published interventions (i.e. the materials screened for inclusion in systematic reviews) have been found to mention the active components of the intervention in only 56% of published descriptions compared with over 90% in pharmacological interventions.42 The TIDieR checklist and guide for reporting all types of interventions was developed using consensus methods with international participants from several disciplines and proposes a minimum set of information: brief name, why (rationale), what materials, what procedure, who provided, how, where, when and how much, tailoring, changes, how well monitored and how well delivered.16 However, for BCIs, further information is required to specify the active ingredients, that is ‘components within an intervention that can be specifically linked to its effect on outcomes such that, if they were omitted, the intervention would be ineffective’.42

The content, or active components, of BCIs are often described in intervention protocols and published reports with different labels (e.g. ‘self-monitoring’ may be labelled ‘daily diaries’) and the same labels may be applied to different techniques (e.g. ‘behavioural counselling’ may involve ‘educating patients’ or ‘feedback, self-monitoring, and reinforcement’).43 This may lead to uncertainty, confusion and difficulties in determining the efficacy of specific change approaches; for example, Morton et al.44 had considerable difficulty in identifying the necessary components of motivational interviewing and as a result found it difficult to synthesise evidence of efficacy. Further, behavioural medicine researchers and practitioners have reported low confidence in their ability to replicate highly effective behavioural interventions for type 2 diabetes mellitus prevention.45 The absence of standardised definitions and labels for intervention components means that systematic reviewers develop their own systems for classifying behavioural interventions and synthesising study findings [e.g. Hardeman et al.,18 Albarracín et al.,19 Mischel (Presidential address given at the Association for Psychological Science Annual Convention, Washington, DC; 2012) and West et al.46]. This proliferation of systems leads to duplication of effort and undermines the potential to accumulate evidence across reviews. It also points to the urgent need for consensus. Consequently, the UK MRC guidance5 for developing and evaluating complex interventions called for improved methods of specifying and reporting intervention content in order to address the problems of lack of consistency and consensus.

A method developed for this purpose is the reliable specification of interventions in terms of BCTs.20 Previous classification systems have mainly been developed for particular behavioural domains (e.g. physical activity, smoking, alcohol consumption or safer sex). Abraham and Michie20 developed the first cross-behaviour BCT taxonomy, building on previous intervention content analyses.18,19 The taxonomy demonstrated reliability in identifying 22 BCTs (e.g. ‘self-monitoring’) and four BCT packages (e.g. ‘relapse prevention’). Identifying the presence of BCTs in intervention descriptions included in systematic reviews and national datasets of outcomes has allowed the identification of BCTs associated with effective interventions.46,47 Effective BCTs have been identified for interventions to increase physical activity and healthy eating,23,48 and to support smoking cessation,27,46 reduce excessive alcohol consumption,29 prevent sexually transmitted infections19,30 and change professional behaviour.49

Although the subsequent development of classification systems of defined and reliably identifiable BCTs has been accompanied by a progressive increase in their comprehensiveness and clarity, this work has been conducted by only a few research groups, but with each developing their own methodology. For this method to maximise scientific advance, collaborative work was needed to develop agreed labels and definitions and reliable procedures for their identification and application across behaviours, disciplines and countries. Therefore, the aim of study 1 was to develop a taxonomy that comprises an extensive list of clearly labelled, well defined BCTs that (1) are proposed as the active components of BCIs, (2) are distinct (non-overlapping, non-redundant) and precise, (3) can be used with confidence to describe interventions, and (4) have a breadth of international and disciplinary agreement.


This study is also published as Michie et al.40


Participants were international behaviour change experts (i.e. active in their field and engaged in investigating, designing and/or delivering BCIs) who had agreed to take part in one or more of the project phases or were members of the IAB50 or of the study team (which included a ‘lay’ person). All board members, as leaders in their field, were eligible to take part as a behaviour change expert. However, in light of their advisory role commitments, members were not routinely approached for further participation except to help widen participation in terms of country, discipline and behavioural expertise.

For the Delphi exercise, 19 international behaviour change experts were invited to take part. Experts were identified from a range of scientific networks on the basis of breadth of knowledge of BCTs, experience of designing and/or delivering BCIs, and of being able to complete the study task in the allotted time. Recruitment was by e-mail, with an offer of an honorarium of £140 (approximately US$230; conversion as of March 2014) on completing the task. Of the 19 originally approached, 14 agreed to take part (response rate of 74%). Ten participants were female, with an age range of 37–62 years [mean = 50.57 years; standard deviation (SD) = 7.74 years]. Expert participants were from the UK (8), Australia (2), the Netherlands (2), Canada (1) and New Zealand (1). Eleven were psychologists (six health psychologists, one clinical psychologist, three clinical and health psychologists and one educational psychologist); one was a cognitive–behaviour therapist and two had backgrounds in health sciences or community health. Eleven were active practitioners in their discipline. Eleven had research or professional doctorates and two had registered psychologist status. There was a wide range of experience of using BCTs, with all having used at least six BCTs, more than half having used more than 30 BCTs and four having used more than 50 BCTs for intervention design, delivery and training.

For the international feedback phase, 16 out of the 30 IAB members took part in discussions to comment on a prototype BCT classification system. IAB members were identified by the study team as being leaders in their field within the key domains of interest (e.g. types of health-related behaviours, major disease types, disciplines such as behavioural medicine) following consultation of websites, journals, and scientific and professional organisations. IAB members were from the USA, Canada, Australia, UK, the Netherlands, Finland and Germany (see Appendix 2). Feedback was also provided by members of the study team, who had backgrounds in psychology and/or implementation science and a ‘lay’ person with a Bachelor of Arts with Honours [BA (Hons)] in English but no background in psychology or behaviour change.


Participants provided written consent and were assured that their responses would remain confidential. All participants were asked to provide demographic information (i.e. age, sex and nationality). Delphi participants were also asked to provide their professional background (i.e. qualifications, registrations, job title and area of work) and how many BCTs they had used professionally in intervention design, face-to-face delivery and training (reported in increments of 5 up to 50 +).

A prototype classification system was developed by the study team based on all known published classifications of BCTs following a literature review37 (step 1). An online Delphi-type exercise51 with two ‘rounds’ was used for initial evaluation and development of the classification system. Participants worked independently and rated the prototype BCT labels and definitions on a series of questions designed to assess omission, overlap and redundancy (step 2). The results of step 2 subsequently informed the development of an improved BCT list. The BCTs identified as requiring further clarification were sent to the Delphi participants for the second round. They were asked to rate BCTs for clarity, precision, distinctiveness and confidence of use (step 3). The resulting list of BCTs was then scrutinised by the IAB, who submitted verbal and written feedback (step 4), and was assessed by the lay and expert members of the study team (step 5). Following each of steps 2–4, the results were synthesised by SM and MJ in preparation for the next step.

Step 1: developing the prototype classification system

The labels and definitions of distinct BCTs were extracted from six BCT classification systems identified by a literature search (the relevant papers are marked with an asterisk in the reference section). For BCTs with two or more labels (n = 24) and/or definitions (n = 37), five study team members rated their preferred labels and definitions. Where there was complete or majority agreement, the preferred label and/or definition was retained. Where there was some, little or no agreement, new labels and definitions were developed by synthesising the existing labels and definitions across classification systems. Definition wording was modified to include active verbs and to be non-directional (i.e. applicable to both the adoption of a new wanted behaviour and the removal of an unwanted behaviour).

Step 2: Delphi exercise first round

Participants were provided with the study definition of a BCT,8 that is having the following characteristics: (1) aim to change behaviour, (2) are proposed ‘active ingredients’ of interventions, (3) are the smallest components compatible with retaining the proposed active ingredients, (4) can be used alone or in combination with other BCTs, (5) are observable and replicable, (6) can have a measurable effect on a specified behaviour(s), and (7) may or may not have an established empirical evidence base. It was explained that BCTs could be delivered by someone else or self-delivered.

The BCTs (labels and definitions) from step 1 were presented in a random order and participants were asked five questions about each of them:

  1. Does the definition contain what you would consider to be potentially active ingredients that could be tested empirically? Participants were asked to respond to this question using a 5-point scale (‘definitely no’, ‘probably no’, ‘not sure’, ‘probably yes’ and ‘definitely yes’).
  2. Please indicate whether you are satisfied that the BCT is conceptually unique or whether you consider that it is redundant or overlapping with other BCTs. (With forced choice as to ‘whether it was conceptually unique, redundant, or overlapping’.)
  3. If participants indicated that the BCT was ‘redundant’, they were asked to state why they had come to this conclusion.
  4. If they indicated that the BCT was ‘overlapping’, they were asked to state: (1) with which BCT(s) and (2) whether or not they can be separated (‘yes’ or ‘no’)’.
  5. If the BCTs were considered to be separate, participants were asked how the label or definition could be rephrased to reduce the amount of overlap or, if not separate, which label and which definition was better.

Participants were given an opportunity to make comments on the exercise and to detail any BCTs not included on the list. They were asked, ‘does the definition and/or label contain unnecessary characteristics and/or omitted characteristics?’ with an open-ended response format. The exercise was designed to take 2 hours, follow-up reminders were sent to participants after 2 weeks and all responses were submitted within 1 month of the initial request.

Frequencies, means and/or modes of responses to questions (1) and (2) were considered for each BCT. Based on the distribution of responses, BCTs for which (a) more than one-quarter of participants doubted that they contained active ingredients and/or (b) more than one-third considered them to be overlapping or redundant were flagged as ‘requiring further consideration’. These data, along with the responses to questions (3) to (4), guided the rewording of BCT labels and definitions, and the identification of omitted BCTs. The BCTs for reconsideration and the newly identified BCTs were presented in the second Delphi exercise round.

Step 3: Delphi exercise second round

The BCTs identified as requiring further consideration were presented. The rest of the BCTs were included for reference only, to assist judgement about distinctiveness. For each BCT, participants were asked three questions and asked to respond using a 5-point scale (‘definitely no’, ‘probably no’, ‘not sure’, ‘probably yes’ and ‘definitely yes’).

  1. If you were asked to describe a BCI in terms of its component BCTs, would you think the following BCT was (a) clear, (b) precise, (c) distinct?
  2. Would you feel confident in using this BCT to describe the intervention?
  3. Would you feel confident that two behaviour change researchers or practitioners would agree in identifying this BCT?

If participants responded ‘probably no’, ‘definitely no’, or ‘not sure’, to any question, they were asked to state their suggestions for improvement.

Frequencies, means and/or modes were calculated for all questions for each BCT. BCTs for which more than one-quarter of participants responded ‘probably no’, ‘definitely no’ or ‘not sure’ to any question were flagged as needing to be given special attention. Using information on the distribution of ratings, the modal scores and suggestions for improvement, SM and MJ amended the wording of definitions and labels. This included changes to make BCTs more distinct from each other when this had been identified as a problem and to standardise wording across BCTs. When it was not obvious how to amend the BCT from the second round responses, other sources (e.g. Vandenbos52) were consulted for definitions of particular words or descriptions of BCTs.

Step 4: feedback from the International Advisory Board

Sixteen out of the 30 members of the IAB took part in one of three, 2-hour long teleconferences to give advice to the study team, and the BCT list was refined based on their feedback.

Step 5: feedback from study team members

The BCT definitions were checked to ensure that they contained an active verb specifying the action required to deliver the intervention.53 The ‘lay’ member of the study team (FR, see Acknowledgments) read through the list to ensure syntactic consistency and general comprehensibility to those outside the field of behavioural science. Subsequently, the study team members made a final check of the resulting BCT labels and definitions.


All data tables for this chapter are reported elsewhere, please refer to Michie et al.40 The evolution of the taxonomy at the different steps of the procedure is summarised in Michie et al.40

Step 1: developing the prototype classification system

Demographic information about the experts involved is summarised in Michie et al.40 Of the 124 BCTs in the prototype classification system, 31 were removed: five composite BCTs and 26 BCTs overlapping with others, which were rated to have better definitions. One additional BCT was identified by the study team, given a label and definition and added to the system. This produced a list of 94 BCTs.

Step 2: Delphi exercise first round

The means, modes and frequencies of responses to the Delphi exercise first-round questions are shown in Michie et al.40 On the basis of these scores, 21 BCTs were judged to be ‘satisfactory’ and 73 ‘requiring further consideration’. Of the 73 reconsidered BCTs, four were removed, four were divided and one BCT was added, giving 74 BCTs. During this process, one reason for overlap became evident: there was a hierarchical structure meaning that deleting overlapping BCTs would end up with only the superordinate BCT and a loss of specific variation (e.g. adopting the higher order BCT ‘consequences’ would have deleted ‘reward’).

Step 3: Delphi exercise second round

The means, modes and frequencies of responses to the five Delphi exercise second round questions are shown in Michie et al.40 On the basis of these scores, 38 BCTs were judged to be ‘satisfactory’ and 32 ‘requiring further consideration’. Of the 70 BCTs reconsidered, seven labels were amended, 35 definitions were rephrased and seven BCTs were removed, giving 63 BCTs. Together with the 21 BCTs judged to be ‘satisfactory’ in the first round, there were 84 BCTs at the end of the Delphi exercise. Some further standardisation of wording across all BCTs was made by study team members (e.g. specifying ‘unwanted’ or ‘wanted’ behaviours rather than the more generic ‘target’ behaviours and ensuring that all definitions included active verbs).

Step 4: feedback from the International Advisory Board

The IAB members made two general recommendations: first, to make the taxonomy more usable by empirically grouping the BCTs and second, to consider publishing a sequence of versions of the taxonomy (with each version clearly labelled) that would achieve a balance between stability/usability and change/evolution. Feedback from members led to the addition of two and the removal of four BCTs.

Step 5: feedback from study team members

Further refinement of labels and definitions by study team members resulted in a list of 93 clearly defined, non-redundant BCTs (see Appendix 2, Table 19). The full evolution of the taxonomy across the five steps is shown in Figure 1.

FIGURE 1. Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram to show evolution of the taxonomy: labels and definitions of BCTs modified.


Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram to show evolution of the taxonomy: labels and definitions of BCTs modified.


An extensive list of 93 distinct, non-redundant BCTs was developed with labels and definitions refined to capture the smallest components compatible with retaining the proposed active ingredients with the minimum of overlap: BCTTv1 (see Appendix 2, Table 19). Development comprised a series of consensus exercises involving 35 experts in delivering and/or designing BCIs. These experts were drawn from a variety of disciplines including psychology, behavioural medicine and health promotion, and from seven countries (the USA, Canada, Australia, UK, the Netherlands, Finland and Germany). Therefore, the resulting BCTs have relevance among experts from varied behavioural domains, disciplines and countries, and potential relevance to the populations from which they were drawn. Evidence is already emerging to suggest that some BCTs from BCTTv1 occur more frequently than others in descriptions of BCIs.40 These BCTs are marked with an asterisk in Table 19 (see Appendix 2).

The extent to which BCTTv1 is applicable without adaptation across behaviours, disciplines and countries is an important question for future monitoring and research. The process of building a shareable consensus language and methodology is necessarily collaborative and will be an ongoing cumulative and iterative process, involving an international network of advisors and collaborators.50 The balance of stability to allow accumulation of knowledge and development to incorporate significant bodies of new knowledge and experience means that classificatory systems are updated at strategic intervals.37 Examples where this has happened are Linnaeus’s classification of plants and systems based on consensus such as the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition54 or the International Classification of Diseases and Related Health Problems, Tenth Edition.55

There was no prior agreed methodology for this work and there are limitations to the methods we have used. The purpose of the Delphi exercise was to develop a prototype taxonomy on which to build. It was the first in a series of exercises adapted to develop the taxonomy. Our Delphi-type methods involved 14 individuals, an appropriate number for these methods,51 but a number that makes the choice of participants important. We attempted to ensure adequate coverage of behaviour change experts. Although we had some diversity of expertise, we acknowledge the predominance of European experts from a psychological background within our sample. At various stages we made arbitrary decisions such as the cut-offs for amending BCT labels and descriptions. In the absence of agreed standards for such decisions, we were guided by the urgent need to develop an initial taxonomy that was fit for purpose and would therefore form a basis for future development. Our amendments of the BCT labels and definitions also depend on the expertise available and, therefore, we based our amendments on a wide range of inputs – the data we collected from Delphi participants and coders, expert modification, international advice and lay user improvements.

The BCTTv1 encompasses a greater number of BCTs than previous taxonomies. Therefore, it requires structure to facilitate recall and access to the BCTs, and thus increase speed and accuracy of use. A true, that is hierarchically structured, taxonomy provides the advantage of making it more coherent to, and useable by, those applying it.37 As the number of identified BCTs has increased, so also has the need for such a structure, to improve the usability of the taxonomy.

Simple, reliable grouping structures have previously been used by three groups of authors. Dixon and Johnston33 grouped BCTs according to ‘routes to behaviour change’, ‘motivation’, ‘action’ and ‘prompts/cues’; Michie et al.27 grouped according to ‘function’ in changing behaviour, ‘motivation’, ‘self-regulation capacity/skills’, ‘adjuvant’ and ‘interaction’; and Abraham et al.30 grouped according to ‘change target’, that is ‘knowledge’, ‘awareness of own behaviour’, ‘attitudes’, ‘social norms’, ‘self-efficacy’, ‘intention formation’, ‘action control’, ‘behavioural maintenance’ and ‘change facilitators’. In order to achieve our aim of a structured taxonomy that is acceptable and useable over diverse disciplines and theoretical orientations, we used a basic method of grouping that does not depend on a theoretical structure. In the next study, we therefore adopted an empirical, ‘bottom-up’ method to developing a consensus of BCT groupings.