Table A2.

Relative risk ratios from two-level multinomial logistic regression models of school socioeconomic composition on sexual initiation between two waves (ref: (1) had no sex by wave 2), males, 2011–2013

	(1)		(2)		(3)		(4)
	(1) had no sex by wave 2 vs. (3) already had sex by wave 1	(1) had no sex by wave 2 vs. (4) lost-to-follow-up at wave 2	(1) had no sex by wave 2 vs. (3) already had sex by wave 1	(1) had no sex by wave 2 vs. (4) lost-to-follow-up at wave 2	(1) had no sex by wave 2 vs. (3) already had sex by wave 1	(1) had no sex by wave 2 vs. (4) lost-to-follow-up at wave 2	(1) had no sex by wave 2 vs. (3) already had sex by wave 1	(1) had no sex by wave 2 vs. (4) lost-to-follow-up at wave 2
School socioeconomic composition	0.716***	0.815**	0.799***	0.805**	0.766***	0.825*	0.786***	0.895
Individual-level
Age			1.544***	1.191***	1.542***	1.193***	1.543***	1.187***
Chewas (ref.)
Tumbuka			1.088	1.255	1.090	1.262	1.084	1.261
Yao			1.627*	1.705**	1.591*	1.712**	1.582*	1.725**
Ngoni			1.036	1.014	1.001	1.029	0.995	1.033
Others			1.363	1.202	1.328	1.218	1.319	1.228
Math performance			0.950	0.934	0.967	0.925	0.967	0.928
Top 10% wealth index			0.854	1.317	0.895	1.298	0.902	1.281
Parent’s secondary education completed			1.155	1.363**	1.129	1.375**	1.134	1.364**
Father’s high occupational status			0.822	0.865	0.818	0.864	0.819	0.865
Both parents (ref.)
Mother only			0.779	0.919	0.772	0.923	0.772	0.905
Father only			1.688	1.246	1.683	1.241	1.693*	1.233
No parents			2.101***	1.472*	2.131***	1.484*	2.127***	1.501*
School-level
Average class size					1.000	0.997	0.998	0.993
Rurality					0.642	1.260	0.574*	1.174
Conventional					0.475***	0.549	0.749	1.098
Secondary School
% Have ever repeated							0.991	1.013
% Satisfied with school							0.984*	0.977*
Mean study after school							0.604	0.370*
Constant	0.524***	0.582***	0.000***	0.031***	0.000***	0.041***	0.008	9.678
N (Schools)	33	33	33	33	33	33	33	33
N (Students)	3950	3950	3950	3950	3950	3950	3950	3950

^*p < 0.05,

^**p < 0.01

^***p < 0.001