Table 4.

Barriers to recruitment

Recruitment barriers	Solution for the main trial phase
In some schools, higher than expected proportions of pupils did not have a mobile telephone (meaning they did not meet eligibility criteria for participation)	No solution possible
Pupils sometimes struggled to accurately complete the combined consent and contact form, leading to a high number of queries, which took time to resolve	Consent form and contact form separated for the main trial to streamline the consent process. Contact form completed at the time of baseline data collection, so a researcher can give assistance to pupils and support completion and reduce errors
Pupils were sometimes unable to remember their mobile telephone number and were not permitted to access their mobile telephones on school premises due to school rules	Researcher available on school site to support pupil completion. Consent form and contact form separated. Contact form completed outside of usual classroom situation, with permission from school senior leadership for pupils to access mobile phone to check number
Pupils sometimes struggled to understand the language used in the consent forms, despite best efforts to make the consent form appropriate for pupils (e.g. some pupils did not understand the word ‘signature’)	Further simplification of the forms was undertaken. Further PPI review by Chilypep. Researcher available on school site to support pupil completion
The two optional consent statements on the paper consent form appeared to make completing the consent form more complicated or confusing for pupils	The optional consent statement giving permission to be contacted for future projects was removed. The optional consent statement relating to permission for future data linkage with routine data sources was made non-optional, to be consistent with all other consent statements. All consent statements on the consent form had to be initialled or marked to indicate agreement in order for the consent form to be valid
Delays caused by other competing demands in school, such as Ofsted inspections, which lead to researchers’ planned days to be onsite to support recruitment being postponed or schools planned sessions for pupils to complete consent forms being postponed	No solution possible
Changes to the leadership or organisation of schools lead to barriers in organising planned session for recruitment	LRTs to endeavour to keep in close communication with identified key contacts
A 2-week window for pupils to consent, after the parent/carer 2-week opt-out window had passed, delayed the recruitment process	As pupils heard about BRIGHT in an assembly before the opt-out window, and information was sent home, an additional 2-week window was deemed unnecessary. Therefore, the requirement to wait 2 weeks for pupils to consent after the parent/carer opt-out window was dropped for the main trial