Table 1 Content and rationale behind behaviour change techniques selected for inclusion within the intervention

Goal Setting (behaviour & outcome)

Set or agree a goal defined in terms of the behaviour to be achieved and the positive outcomes of the behaviour change.

The paper based, online and app based intervention materials will encourage TYA cancer survivors to identify a target behaviour and a set goals to change.

Problem Solving

Analyse, or prompt the person to analyse, factors influencing the behaviour and generate or select strategies that include overcoming barriers and/or increasing facilitators.

The paper based, online and app based intervention materials encourage TYA cancer survivors to think creatively of strategies to change their behaviour by writing down ideas which might work for them.

Action Planning

Prompt detailed planning of performance of the behaviour (must include at least one of context, frequency, duration and intensity).

The paper based, online and app based intervention materials will contain ‘Healthy Life Action Plan’ sheets which are designed to encourage participants to plan how they will fit the new action into their existing routines.

Behaviour Substitution

Prompt substitution of the unwanted behaviour with a wanted or neutral behaviour.

The paper based online and app based intervention materials contain information and tips ‘ideas for everyday change’ on new actions which could be incorporated into a daily routine to help TYA cancer survivors meet their daily goals.

Habit Formation

Prompt rehearsal and repetition of the behaviour in the same context repeatedly so that the context elicits the behaviour.

The paper based online and app based intervention materials will contain advice about forming habits and specifically repeating the same actions in similar contexts.

Habit Reversal/Substitution

Prompt rehearsal and repetition of an alternative behaviour to replace an unwanted habitual behaviour.

The paper based online and app based intervention materials will contain information on the importance of repeating new actions.

Feedback on behaviour

Monitor and provide information or evaluative feedback on performance of the behaviour.

The online and app based interventions will contain features where young people receive a score or result based upon their health behaviour.

Self-monitoring of behaviour

Establish a method for the person to monitor and record their behaviour as part of a behaviour change strategy.

The paper based, online and app based intervention materials will contain ‘Healthy Life Action Plan’ sheets which are designed to encourage participants to monitor the change in their behaviour over time.

Information about health consequences

Provide information about health consequences of performing the behaviour.

The paper based online and app based intervention materials will contain information about the potential benefits and costs of either having a healthy lifestyle or not having a healthy lifestyle.

Prompts/ Cues

Introduce or define environmental or social stimulus with the purpose of prompting or cueing the behaviour. The prompt or cue would normally occur at the time or place of the performance.

The intervention app will contain a feature to send automated reminders to TYA cancer survivors phones prompting healthy lifestyle behaviours.

Social Support (un-specified)

Advise on, arrange or provide social support (e.g. from friends, relatives, colleagues, buddies and staff) or non-contingent praise or reward for performance of the behaviour. It includes encouragement and counselling, but only when it is directed at the behaviour.

The paper based, online and app based intervention materials will advise participants to find a close friend or family member to encourage continuation with the behaviour change programme.

The online intervention will include a message forum encouraging young people to communicate and praise one another for their achievements. The message forum will also encourage young people to share how they have changed their behaviours, the barriers they came across and how they addressed these challenges.

Social Comparison

Draw attentions to others’ performance to allow comparison with the persons’ own performance

The online intervention will include a message forum where TYA cancer survivors will be able to share and compare their behaviours with other young people.