Table 2

Overview of codesign input sources and data contributions

Input	Participants	Study stage	Time frame	Demographic information		Mode of contribution to codesign	Output generated
PPI/stakeholder group (headteachers×2; parents×2; voluntary/community sector mental health in schools expert)	N=5	Stages 1–4	Pre study—month 12	Age, mean (SD)	49.3 (7.4)	Regular meetings to share findings and discussion of study progress.	The dedicated PPI/stakeholder group members are part of the research team and provided guidance and recommendations on study findings and developments.
	N=5	Stages 1–4	Pre study—month 12	Females (n)	2
Practitioners who provide mental health support in schools	N=2	Stage 1	Months 1–2	Age, mean (SD)	54.5 (12.0)	Focus group interview conducted face to face (qualitative).	Perceptions of how the screening/intervention procedures should be introduced in schools, delivered, concerns and possible solutions.
	N=2	Stage 1	Months 1–2	Females (n)	2	Focus group interview conducted face to face (qualitative).
	N=15	Stage 4	Months 6–8	Age, mean (SD)	38 (10.5)	Semistructured interviews conducted remotely (qualitative).
	N=15	Stage 4	Months 6–8	Females (n)	14	Semistructured interviews conducted remotely (qualitative).
Y4 children	N=8	Stage 1	Months 1–2	Age range, years	8–9	Focus group interview conducted face to face (qualitative).	Perceptions of how the screening/intervention procedures should be introduced to the class, carried out, concerns and possible solutions.
	N=8	Stage 1	Months 1–2	Females (n)	6	Focus group interview conducted face to face (qualitative).
	N=29	Stage 2	Months 2–6	Age, mean (SD)	8.5 (0.6)	Completed screening questionnaires for likely anxiety problems (quantitative).	Identification of children who are likely to have problems with anxiety.
	N=29	Stage 2	Months 2–6	Females (n)	19
	N=2	Stage 4	Months 6–8	Age, mean (SD)	9 (0)	Semistructured interviews conducted remotely (qualitative).	Experience of the screening pathway and intervention.
	N=2	Stage 4	Months 6–8	Females (n)	2	Semistructured interviews conducted remotely (qualitative).	Experience of the screening pathway and intervention.
Y4 parents	N=7	Stage 1	Months 1–2	Age, mean (SD)	43.7 (3.6)	Focus group interview conducted face to face (qualitative).	Perceptions of how the screening/intervention procedures should be introduced to families, delivered in schools, concerns and possible solutions.
	N=7	Stage 1	Months 1–2	Females (n)	6	Focus group interview conducted face to face (qualitative).
	N=29	Stage 2	Months 2–6	Age, mean (SD)	42.0 (3.4)	Completed screening questionnaires for likely anxiety problems (quantitative).	Identification of children who are likely to have problems with anxiety.
	N=29	Stage 2	Months 2–6	Females (n)	24
	N=2	Stage 3	Months 5–6	Age, mean (SD)	46.5 (0.7)	Cued-recall interviews conducted via telephone (qualitative).	Experience of the screening pathway and receiving feedback on scores.
	N=2	Stage 3	Months 5–6	Females (n)	2
	N=7	Stage 4	Months 6–8	Age, mean (SD)	43.6 (2.2)	Semistructured interviews conducted remotely (qualitative).	Experience of the screening pathway and intervention. Includes parents who dropped out (n=2).
	N=7	Stage 4	Months 6–8	Females (n)	6	Semistructured interviews conducted remotely (qualitative).
Parents in challenging circumstances	N=10	Stage 4	Months 5–12	Age, mean (SD)	47.1 (7.6)	Semistructured interviews conducted remotely (qualitative).	Perceptions of how a school screening/intervention pathway could be delivered in schools and possible barriers/facilitators to taking part.
Parents in challenging circumstances	N=10	Stage 4	Months 5–12	Females (n)	7	Semistructured interviews conducted remotely (qualitative).
School staff	N=6	Stage 1	Months 1–2	Age, mean (SD)	48.0 (7.4)	Focus group interview conducted face to face (qualitative).	Perceptions of how the screening/intervention procedures should be introduced, delivered, concerns and possible solutions.
	N=6	Stage 1	Months 1–2	Females (n)	6	Focus group interview conducted face to face (qualitative).
	N=4	Stage 2	Months 2–6	Age, mean (SD)	41.8 (8.3)	Screening questionnaires for likely anxiety problems (quantitative).	Identification of children who are likely to have problems with anxiety.
	N=4	Stage 2	Months 2–6	Females (n)	2
	N=5	Stage 4	Months 6–9	Age, mean (SD)	41.6 (7.2)	Semistructured interviews conducted remotely (qualitative).	Experience of the screening pathway, perceptions of the intervention offered to families and perceived barriers/facilitators to uptake in schools.
	N=5	Stage 4	Months 6–9	Females (n)	3	Semistructured interviews conducted remotely (qualitative).

PPI, patient and public involvement; Y4, year 4.