The person-based approach to planning interventions

The PBA commonly uses five activities that are useful for developing, describing, and refining the ‘programme theory’ for the intervention, i.e. the description of how the intervention should work, for whom, and in what circumstances. More information about these activities can be found on the PBA website here, and a summary of each has been provided below.

Reviewing / synthesising relevant literature

• An initial theory of how intervention should work can be created by drawing on relevant theory and evidence
• Qualitative and mixed methods of evaluations of similar interventions are useful to understand barriers and facilitators influencing intervention engagement

User needs studies

• Studies may be needed to address unanswered questions or gaps in the literature
• Method choice will depend on the research question
• Qualitative studies (e.g. focus groups, interviews, ethnography) are helpful for developers to understand user needs, perspective, and context

Logic model / ‘theory of change’

• A diagram that summarises the cause-effect sequence, describing how the key elements of the intervention should lead to positive behaviour change and better health
• This model is best practice to most intervention development approaches so there is guidance available

Intervention planning table

• This brings together all the available evidence about the intervention elements that are needed and why, drawing on theory, research, and expertise from all members the intervention development team
• Captures key pieces of information and early decisions all in one place

Guiding principles for intervention design

• The guiding principles focus on what is needed to make the intervention acceptable, feasible, and engaging for the users it is designed for
• These can keep the development focused on what will be especially appealing and useful to intended users

Creating good guiding principles

The aim of guiding principles is to highlight how the intervention will address key issues crucial to engagement in the specific context of the target users. To achieve this we:

1. Identify the specific user characteristics likely to affect engagement, such as their views, needs and capabilities (see first column of table below)
2. Identify key intervention design objectives to improve engagement – what the intervention design must achieve to meet these specific needs or overcome these specific barriers
3. Identify key features of the intervention that will achieve those objectives. Key features can include behaviour change techniques (from intervention planning – e.g. goal setting), delivery characteristics (e.g. video format), implementation setting (e.g. schools), communication methods (e.g. framing), navigation methods (e.g. tunnelling, self-tailoring), or any other aspect of the intervention that could affect engagement.

There are four ‘golden rules’ of the guiding principles. Each of these are shown in the following infographic.

Examples of Guiding Principles

The example in the following table shows one guiding principle for designing a digital intervention to encourage older people to become more physically active.

This would likely be one of several guiding principles for this intervention – others might focus on addressing different user characteristics or contextual issues that are relevant to older adults’ physical activity behaviour. These would have different design objectives and intervention features to address those specific issues.

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