CACTIS Tool v1.8.1

Welcome to CACTIS v1.8.1

CACTIS provides a step-by-step process for developing behaviour change intervention strategies. It guides you through specifying a behavioural goal, conducting a COM-B diagnosis to identify capability, opportunity and motivation factors to target, then selecting appropriate intervention functions and behaviour change techniques. It then constructs a structured prompt for an AI tool such as Claude to generate a draft strategy.

Specify the Problem

Enter the behavioural goal, target population/group, and intervention setting(s). Be precise and observable.

Identify COM-B Targets

For each of the 27 COM-B factors, indicate relevance/room for improvement and strength of evidence. CACTIS auto-assigns priority. Expand on High priority targets to add evidence and rationale.

Select BCTs

For High priority COM-B targets, select Behaviour Change Techniques across the 9 BCW Intervention Functions. Multiple BCTs can be selected per cell.

Generate Results & Prompt

View all your selections and copy a structured LLM prompt. Paste this into Claude or another AI tool to generate a draft intervention strategy.

💡 Tip: Your work is saved automatically in your browser session. Use Save to file to save a permanent copy, and Restore from file to restore it later.

📄 Open source & licensing: This tool is open source and free to use. Please note that CACTIS is presented as is and users take responsibility for any and all consequences of its use. Use of CACTIS should be acknowledged in any reports along the lines of ‘The CACTIS tool version 1.8.1 (see https://com-b.org/cactis) was used in the development of this intervention. The authors of CACTIS bear no liability for any adverse consequences of its use.’

📊 BCT Reference Workbook
Download the full BCT mapping reference as an Excel workbook — includes the complete BCT reference list, a de-duplicated list of BCTs, a list of BCT × Intervention Function combinations, the COM-B × Intervention Function mapping matrix, intervention function definitions, and a COM-B quick reference.

Step 1: Specify the Problem

🎯 Behavioural Goal

Describe the specific behaviour you want to promote or reduce. Be precise: what is the behaviour, in what direction, how much, and by when?

👥 Target Population, Group or Person

Describe who the intervention is aimed at. Include relevant characteristics such as age, health status, geography, or setting.

📍 Intervention Setting(s)

Where will the intervention take place? Include all relevant settings.

⚙️ Implementation and Delivery Constraints

Optional. Describe any constraints already in place regarding how the intervention will be delivered — e.g. mode of delivery, policy options, budget, timing. Leave blank if none.

Step 2: Identify COM-B Targets

For each factor, use the dropdowns to indicate room for improvement and evidence strength. CACTIS will automatically assign a priority. Use the ▸ Expand button on high priority targets to add evidence and rationale.

Step 3: Select Behaviour Change Techniques

For each High priority COM-B target, click the + button under each Intervention Function to select one or more BCTs. You can select multiple BCTs per cell.

COM-B Target	Priority	Education	Persuasion	Incentivisation	Coercion	Training	Rule-making	Env. Restructuring	Modelling	Enablement

Step 3b: Detail the Selected BCTs

For each BCT you selected, record the rationale for selecting it and what the BCT combination could or should look like in practice. Use the ? buttons for guidance on what each field requires and where the information may come from. Both fields are optional and feed into the LLM prompt in Step 4.

Step 4: Results & LLM Prompt

Download decision record

Export everything entered — the problem definition, full COM-B assessment, selected BCTs with their implementation detail, and the generated prompt — as a formatted Word document. A complete record of the decisions made.

Selected BCTs Summary

LLM Prompt

Copy this prompt and paste it into Claude or another AI tool to generate a draft intervention strategy.

About CACTIS

CACTIS is developed by the Unlocking Behaviour Change CIC (unlockingbehaviourchange.com) with support from The Public Health Wales Behavioural Science Unit. It undergoes continual development in the light of evidence, theory and user experiences.