Findings are reported in line with the TIDieR template for intervention description and replication (TIDieR) checklist and guide (additional file 4).
A total of 32 distinct barriers (20, 7, and 5 across target behaviour areas 1-3) and 30 experiential or intuitive enablers (20, 4, and 6 across target behaviour areas 1-3) were identified through the initial phase of data analysis. The barriers were coded according to distinct TDF domains, and through in-depth discussion, coding was refined, constructs were allocated, and overarching TDF domains were assigned to groups of barriers that were interrelated (Figure 2).
Stage 1 – In depth context clarification and construct coding for identified barriers and enablers
In-depth context clarification revealed crucial insights from the lead interviewer (SB) who had assigned the original TDF codes prior to the discussion[50]. This allowed for drilling down barriers and enablers to the construct level, ensured confidence amongst the group that domains assigned to barriers were appropriate, and in instances where there was some uncertainty, provided an opportunity to unpick coding in relation to the context and make amendments where necessary. The need to change TDF domains to which barriers had been assigned occurred in one case for ‘target behaviour area 1’ (ensure appropriate patients receive testing) and in one case for ‘target behaviour area 2’ (test selection and variant interpretation). For example, a lay description of a barrier: ‘not trained to counsel’ was originally coded under the ‘knowledge’ domain. However, context clarification discussion records indicated: “clinicians talked about this passionately - they weren't trained to counsel people about genomic testing. Re-thinking and wondering whether skills is a better TDF fit”, and so this barrier was recoded to ‘skills’ (see additional file 2).
A total of 32 barriers were coded against TDF domains and constructs, with seven domains represented in total and used between one (e.g., ‘goals’, ‘social influences’) and six (‘skills’) times across each target behaviour area. Eighteen TDF constructs were used between one (e.g., goal priority, professional boundaries) and three (e.g., skill development, competence) times across each target behaviour area (additional file 3). Across all target behaviour areas, there was some overlap of TDF domains (e.g., environmental context and resources, knowledge) and constructs (e.g., person x environment interaction). Target behaviour area 1 (TBA1) (ensuring appropriate patients receive testing) produced the largest number of barriers (n = 20), and range of TDF domains (n = 7) and constructs (n = 13).
Stage 2 – grouping of barriers according to overarching TDF domains:
In-depth context clarification also revealed the overlapping nature and interrelatedness of some barriers, to the extent that a decision was made to group barriers according to ‘overarching TDF domains’. A total of 13 overarching TDF domains were generated, with seven, four, and two overarching domains represented across target behaviour areas 1-3, respectively, each of which encompassed between one and five individual interrelated barriers. As an example, barriers such as ‘lack of clinician genetic literacy’ (TDF: knowledge), ‘overenthusiastic calling of variants’ (TDF: beliefs about capabilities), and ‘lack of confidence in calling variants’ (TDF: beliefs about capabilities) were coded under a general theme of ‘Need for role clarity’, with the corresponding overarching TDF domain being ‘Professional role and identity’.
Stage 3a – Coding intuitive enablers against BCTs:
A total of 21 BCTs were represented within the 30 intuitive enablers found across target behaviour areas 1-3 (see additional file 2), which were found to be used on 49 occasions (‘occasions’ refer to any instance a BCT was identified in an intuitively described implementation strategy, noting that each implementation strategy can contain multiple BCTs, and one BCT can be present in multiple different implementation strategies[35]).
Of the 21 BCTs represented, across all three target behaviour areas, the most frequently used were ‘conserving mental resources’ (represented in seven intuitive enablers), followed by ‘social support practical’ (represented in six intuitive enablers), and ‘credible source’ (represented in five intuitive enablers). The largest number of enablers (n = 20) was produced to address TBA1, which were represented by 14 different BCTs used between one (e.g., ‘graded task’) and six (‘conserving mental resources’) times.
Prior to theory-alignment assessment from the existing evidence-base, using the algorithm described earlier, we hypothesised the MoA for changes to barrier-specific, and subsequently, overarching TDF domains, as a result of intuitively derived context-appropriate enablers retrospectively coded against BCTs, for example (in relation to TBA1– ensuring appropriate patients receive testing):
The construct of Decision making and distinct TDF theme Memory, attention and decision making was selected because the clinicians were confused about the process because it was not clear to them. The enabler of 'clear referral criteria within an informal checklist' is linked to the BCT 'conserving mental resources' because it provides explicit guidance - this should reduce the memory, attention and decision making barrier (distinct TDF theme) by simplifying the process, and enhance their skills (overarching TDF theme) for 'doing genomic testing' by providing clearer circumstances in which to apply genomics in practice.
Stage 3b – designing new implementation strategies using BCTs
A total of 20 original implementation strategies (n=9, n=7, and n=4 across TBAs 1-3, respectively) were developed to address the nine remaining barriers (that did not have any suggested intuitive enablers) using combinations of 20 BCTs (on 30 occasions) that have previously demonstrated mechanistic links with either individual level (n = 17) or overarching (n = 3) TDF-coded domains [4, 6] (additional file 2). For example, the populated algorithm in relation to TBA3– communicating results – would appear as):
The construct of Person x environment interaction and TDF theme Environmental context and resources was selected because the clinicians were hampered and frustrated by the long turn-around times for some test results. The strategy of 'contact point in the labs' and 'develop a test result turnaround time list' is derived from the BCTs 'Social support practical' and 'adding objects to the environment' because clinicians will be able to access accurate information relating to the timing of the tests - this should reduce the environmental context and resource barrier (distinct TDF domain) and, in turn, improve their emotion (overarching TDF theme) by helping them to manage their frustrations around the slow speed of test result turn-around time.
Of the 20 BCTs, across all three target behaviour areas, the most frequently used were ‘adding objects to the environment’ (used four times), followed by ‘social support practical’ and ‘instruction on how to perform the behaviour’ (each used three times).
Stage 4 – assessing alignment of intuitively derived interventions and theory
Table 2 presents a summary of the alignment of intuitively derived interventions and theory. After cross-referencing against the Theory and Techniques Tool[18], across all three target behaviour areas, we found that of the 49 intuitive enabling strategy occasions in which BCTs were represented, nine (18%) aligned with a corresponding distinct TDF domain coded barrier that has previously demonstrated statistically significant mechanistic links (i.e., theoretical alignment agreed upon by expert consensus AND associations in the intervention literature synthesis). For example, TBA1 = 5/31 (16%) – ‘conserve mental resources’ (TDF domain = memory, attention, and decision making), ‘behavioural practice/rehearsal’ (TDF domain = skills), and ‘social support (practical)’ (TDF domain = environmental context and resources; occurred three times). There were 16 (33%) intuitive strategies coded against BCTs that aligned with a corresponding distinct or overarching TDF domain coded barrier, for example TBA1 = 10/31 (32%) – ‘conserve mental resources’ (TDF domain = memory, attention, and decision making) and ‘behavioural practice/rehearsal’ (TDF domain = skills), social support (practical)’ (TDF domain = environmental context and resources; occurred three times); ‘demonstration of the behaviour’ (TDF domain = beliefs about capabilities), ‘salience of consequences’ (TDF domain = beliefs about consequences), ‘behavioural practice/rehearsal’ (beliefs about capabilities), ‘problem solving’ (TDF domain = beliefs about capabilities), and ‘graded task (TDF domain = social influences).
Table 2. Alignment of distinct and overarching barriers and intuitive enabling strategies with theoretical recommendations
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DISTINCT BARRIER AND ENABLING STRATEGY ALIGNMENT WITH THEORETICAL RECOMMENDATIONS
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|
Align with theory
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Non-links
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Inconclusive
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No evidence
|
TBA1
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5/31 (16%)
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• ‘Conserve mental resources’ - Memory, attention, and decision making
• ‘Behavioural practice/rehearsal’ – Skills
• ‘Social support (practical)’ - environmental context and resources; occurred three times
|
4/31 (13%)
|
• ‘Prompts and cues’ -Knowledge
• ‘Credible source’ – Skills
• ‘Conserve mental resources’ – Professional role and identity; used on two occasions
|
5/31 (16%)
|
17/31 (55%)
|
TBA2
|
2/12 (17%)
|
• ‘Information about social and environmental consequences’ – Knowledge
• ‘Social support (unspecified)’ - Social influences
|
2/12 (17%)
|
• ‘Problem solving’, ‘monitoring of outcomes of behaviour without feedback’ – Professional role and identity
|
1/12 (8%)
|
7/12 (58%)
|
TBA3
|
2/6 (33%)
|
• ‘Conserve mental resources’ - Memory, attention, and decision making
• ‘Social support (unspecified)’ - Social influences
|
1/6 (16%)
|
• ‘Action planning’ - Knowledge
|
0/6 (0%)
|
3/6 (50%)
|
Total
|
9/49 (18%)
|
7/49 (14%)
|
6/49 (12%)
|
27/49 (55%)
|
|
OVERARCHING BARRIER AND ENABLING STRATEGY ALIGNMENT WITH THEORETICAL RECOMMENDATIONS
|
|
Align with theory
|
Non-links
|
Inconclusive
|
No evidence
|
TBA1
|
10/31 (32%)
|
• ‘Conserve mental resources’ - Memory, attention, and decision making
• ‘Behavioural practice/rehearsal’ – Skills
• ‘Social support (practical)’ - environmental context and resources; occurred three times
• ‘Demonstration of the behaviour’ - Beliefs about capabilities
• ‘Salience of consequences’ - Beliefs about consequences
• ‘Behavioural practice/rehearsal’ (beliefs about capabilities), ‘problem solving’ - Beliefs about capabilities
• ‘Graded task’ - Social influences
|
4/31 (13%)
|
• ‘Prompts and cues’ -Knowledge
• ‘Credible source’ – Skills
• ‘Conserve mental resources’ - Professional role and identity; used on two occasions
|
5/31 (16%)
|
12/31 (39%)
|
TBA2
|
4/12 (33%)
|
• ‘Information about social and environmental consequences’ – Knowledge
• ‘Social support (unspecified)’ - Social influences
• ‘Information about others approval’ - Social influences
• ‘Social comparison’ - Social influences
|
4/12 (33%)
|
• ‘Problem solving’ - Professional role and identity; used on two occasion
• ‘Monitoring of outcomes of behaviour without feedback’ – Professional role and identity
• ‘Problem solving’ - Social influences
|
2/12 (16%)
|
2/12 (17%)
|
TBA3
|
2/6 (33%)
|
• ‘Conserve mental resources’ - Memory, attention, and decision making
• ‘Social support (unspecified)’ - Social influences
|
1/6 - (13%)
|
• Action planning’ - Knowledge
|
0/6 (0%)
|
3/6 (50%)
|
Total
|
16/49 (33%)
|
9/49 (18%)
|
7/49 (14%)
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17/49 (35%)
|
For distinct barriers, six of the 21 BCTs were found to be ‘non-links’ (e.g., BCT-MoA link absent in literature synthesis AND experts in consensus study agreed there was no theoretical link), used on 7/49 (14%) of occasions: TBA1: ‘prompts and cues’ (TDF domain: knowledge), ‘credible source’ (TDF domain = skills), ‘conserve mental resources’ (TDF domain = professional role and identity; used on two occasions); TBA2: ‘problem solving’ and ‘monitoring of outcomes of behaviour without feedback’ (TDF domain = professional role and identity); TBA3: ‘action planning’(TDF domain: knowledge). However, all of these occasions were in the context of interventions with multiple BCTs coded (see additional file 2), although none of the accompanying BCTs had evidence of mechanistic links (as defined above). Six BCTs were found to be ‘non-links’ for distinct or overarching TDF domain coded barriers used on 9/49 (18%) of occasions: TBA1: no additional non-links found (beyond distinct TDF domains); TBA2: ‘problem solving’ (TDF domain = professional role and identity; used on two occasions), ‘monitoring of outcomes of behaviour without feedback’ (TDF domain: professional role and identity), and ‘problem solving’ (TDF domain = social influences); TBA3: no additional ‘non-links’ found (beyond distinct TDF domains).
Some of the BCT links to theory were found to be inconclusive. For the distinct barriers, there were six (12%) intuitive strategies coded against BCTs found to be inconclusive and seven (14%) for the distinct or overarching barriers. The remaining BCTs had either an absence of evidence to draw conclusions about mechanistic links for distinct barriers [remaining BCTs used on 27/49 (55%) occasions], or distinct or overarching barriers [remaining BCTs used on 17/49 (35%) occasions]; or existing evidence from literature and/or expert consensus was deemed ‘inconclusive’ for distinct barriers [5 BCTs used on 6/49 (12%) occasions], and for distinct or overarching barriers [6 BCTs used on 7/49 (14%) occasions]. Additional file 3 provides levels of evidence and details for mechanistic links for all 49 occasions, as derived from the Theory and Techniques Tool.