Table 1

Participant characteristics

	All (n, 4353)		Boys (n, 2138)		Girls (n, 2215)		Cohort 1 (n, 1593)		Cohort 2 (n, 1421)		Cohort 3 (n, 1339)
	N	%	N	%	N	%	N	%	N	%	N	%
Gender (n, 4353)
Boys	2138	49.1	··	··	··	··	778	48.8	701	49.3	659	49.2
Girls	2215	50.9	··	··	··	··	815	51.2	720	50.7	680	50.8
Cohort (school year group) (n, 4353)
1 (Y7)	1593	36.6	778	36.4	815	36.8	··	··	··	··	··	··
2 (Y8)	1421	32.6	701	32.8	720	32.5	··	··	··	··	··	··
3 (Y9)	1339	30.8	659	30.8	680	30.7	··	··	··	··	··	··
Eligible for free school meals (n, 4113)
No	3137	76.3	1563	77.2	1574	75.4	1142	76.5	1015	75.4	980	76.9
Yes	976	23.7	461	22.8	515	24.7	351	23.5	331	24.6	294	23.1
Ethnic group (n, 4353)
Black African	1113	25.6	545	25.5	568	25.6	383	24.0	374	26.3	356	26.6
Black Caribbean	719	16.5	350	16.4	369	16.7	234	14.7	257	18.1	228	17.0
Other black	127	2.9	51	2.4	76	3.4	49	3.1	46	3.2	32	2.4
Mixed white and black	380	8.7	182	8.5	198	8.9	143	9.0	117	8.2	120	9.0
Other mixed ethnic groups	237	5.4	105	4.9	132	6.0	87	5.5	82	5.8	68	5.1
Indian, Pakistani, Bangladeshi	181	4.2	83	3.9	98	4.4	79	5.0	57	4.0	45	3.4
Latin American	217	5.0	110	5.1	107	4.8	58	3.6	79	5.6	80	6.0
White British	667	15.3	337	15.8	330	14.9	285	17.9	185	13.0	197	14.7
Non-British white	409	9.4	213	10.0	196	8.9	166	10.4	121	8.5	122	9.1
Any other/unknown	303	7.0	162	7.6	141	6.4	109	6.8	103	7.3	91	6.8

The proportion of white British students was slightly higher in Cohort one compared with cohorts 2 and 3 (χ²=40.3223, df=18, p=0.002).