Effects of an e-reader intervention on literacy, numeracy and non-verbal reasoning among adolescent girls in Zambia: evidence from a randomised controlled trial

Figures & data

Table 1. Selected background characteristics, literacy and numeracy assessments, and non-verbal reasoning scores at baseline by arm

Baseline characteristic/assessment	Total (N = 1178)	Arm 1 safe spaces + e-reader (N = 374)	Arm 2 safe spaces (N = 425)	Arm 3 control (N = 379)	P-value joint test
Age at last birthday	12.8 (SD 1.3)	12.8 (SD 1.3)	12.8 (SD 1.3)	12.9 (SD 1.3)	0.952
English spoken at home	25%	26%	24%	25%	0.956
Ever repeated a grade	34%	33%	33%	36%	0.644
Count of household items (0–15)	8.1 (SD 2.8)	8.5 (SD 2.5)	8.0 (SD 2.9)	7.7 (SD 3.0)	0.289
Mother’s education < junior secondary^a	36%	33%	36%	37%	0.844
Mother’s education: don’t know	19%	20%	16%	21%	0.262
Father’s education < junior secondary^a	14%	14%	14%	14%	0.993
Father’s education: don’t know	29%	27%	27%	32%	0.451
Passed UWEZO paragraph^b	53%	58%	48%	53%	0.421
Passed UWEZO story^c	44%	48%	40%	46%	0.542
Passed all UWEZO literacy (scored 6)	39%	41%	35%	40%	0.664
UWEZO literacy score (0–6)	3.4 (SD 2.2)	3.7 (SD 2.2)	3.2 (SD 2.3)	3.5 (SD 2.3)	0.499
Literacy multiple choice score^d(0–32)	13.7 (SD 6.7)	13.8 (SD 6.4)	13.2 (SD 6.5)	14.2 (SD 7.1)	0.782
Passed all UWEZO numeracy (scored 7)	63%	69%^†	60%	62%	0.111
UWEZO numeracy score (0–7)	6.2 (SD 1.4)	6.3 (SD 1.3)^††	6.0 (SD 1.5)	6.2 (SD 1.3)	0.234
Numeracy multiple choice score^d (0–23)	8.4 (SD 4.7)	8.9 (SD 4.6)	7.8 (SD 4.7)	8.7 (SD 4.8)	0.384
Non-verbal reasoning score^e (0–16)	8.9 (SD 3.3)	9.1 (SD 3.2)	8.6 (SD 3.4)	9.0 (SD 3.2)	0.684

P-values from F tests for differences across arms accounting for clustering at the school level to test for baseline balance for the sample interviewed at endline.

^†p < .1 difference Arm 1 vs Arm 3; ^††p < .1 difference Arm 1 vs Arm 2

^a<Junior secondary is equivalent to ≤ 8 years of schooling

^bPassing the paragraph indicates the respondent could read letters, read simple words and read a paragraph out loud containing 3 simple sentences and 20–22 words and make 2 or fewer mistakes.

^cPassing the story indicates the respondent could do all components listed in ‘a’ plus could read a two paragraph 12 sentence story out loud and make 4 or fewer mistakes.

^dScores were imputed for girls who did not pass the UWEZO

^eNon-verbal reasoning score is the total number of correct answers to 16 items from Raven’s Coloured Progressive Matrices.

Table 2. Proportion passing UWEZO literacy (scoring 6) at baseline and endline by number of sessions attended

Arm 1 – E-reader
# of sessions attended	N	Baseline	Endline	Difference
<13	84	0.274	0.476	0.202
13–15	83	0.398	0.602	0.205
16–17	100	0.450	0.670	0.220
18–19	107	0.505	0.794	0.290
Total	374	0.414	0.647	0.233
Arm 2 – Safe spaces only
<13	107	0.224	0.402	0.178
13–15	95	0.253	0.432	0.179
16–17	108	0.370	0.491	0.120
18–19	115	0.513	0.661	0.148
Total	425	0.346	0.501	0.155
Arm 3 – Control
Total	379	0.401	0.541	0.140

Table 3. Proportion passing UWEZO literacy (scoring 6) at baseline and endline by number of sessions attended with entropy weighting

Arm 1 – E-reader
# of sessions attended	N	Baseline	Endline	Difference
<13	84	0.274	0.476	0.202
13–15	83	0.398	0.602	0.205
16–17	100	0.450	0.670	0.220
18–19	107	0.505	0.794	0.290
Total	374	0.414	0.647	0.233
Arm 2- Safe spaces only
<13	107	0.290	0.503	0.213
13–15	95	0.331	0.564	0.233
16–17	108	0.443	0.556	0.113
18–19	115	0.590	0.729	0.138
Total	425	0.426	0.595	0.169
Arm 3 – Control
Total	379	0.450	0.601	0.151

Table 4 Summary of literacy results at endline

	(1)	(2)	(3)	(4)
	Control Arm 3 Endline mean	Safe spaces+ e-reader Arm 1 Coefficient (Robust SE)	Safe spaces only Arm 2 Coefficient (Robust SE)	Arm1 vs Arm 2 Coefficient (Robust SE)
UWEZO literacy
Passed paragraph (=1), unadjusted	0.694	0.036 (0.069)	-0.082 (0.093)	0.118 (0.077)
Adjusted, baseline outcome only		0.002 (0.038)	-0.047 (0.045)	0.049 (0.032)
Adjusted, baseline outcome & covariates		-0.014 (0.025)	-0.043† (0.025)	0.029 (0.020)
Adjusted with entropy weighting		-0.006 (0.025)	-0.031 (0.027)	0.024 (0.020)
Passed story (=1),unadjusted	0.599	0.080 (0.065)	-0.065 (0.097)	0.145† (0.082)
Adjusted, baseline outcome only		0.062† (0.032)	-0.025 (0.045)	0.088* (0.040)
Adjusted, baseline outcome & covariates		0.044† (0.026)	-0.020 (0.026)	0.064* (0.028)
Adjusted with entropy weighting		0.046† (0.025)	-0.001 (0.028)	0.047 (0.028)
Passed all – scored 6(=1), unadjusted	0.541	0.106 (0.077)	-0.040 (0.108)	0.146† (0.085)
Adjusted, baseline outcome only		0.097* (0.036)	-0.004 (0.053)	0.101* (0.044)
Adjusted, baseline outcome & covariates		0.074** (0.026)	0.005 (0.023)	0.069* (0.027)
Adjusted with entropy weighting		0.064* (0.025)	0.011 (0.029)	0.052† (0.029)
Score (0-6), unadjusted	4.235	0.361 (0.323)	-0.289 (0.464)	0.650 (0.384)
Adjusted, baseline outcome only		0.234† (0.137)	-0.067 (0.168)	0.301* (0.139)
Adjusted, baseline outcome & covariates		0.177 (0.114)	-0.049 (0.112)	0.226* (0.106)
Adjusted with entropy weighting		0.196† (0.112)	0.007 (0.122)	0.189† (0.104)
Multiple choice literacy
Score (0-32),unadjusted	17.858	0.423 (1.652)	-1.709 (2.022)	2.133 (1.664)
Adjusted, baseline outcome only^1		0.494 (0.464)	-0.590 (0.551)	1.084* (0.408)
Adjusted, baseline outcome & covariates^1		0.195 (0.332)	-0.591† (0.323)	0.786** (0.249)
Adjusted with entropy weighting^1		0.282 (0.345)	-0.439 (0.341)	0.721* (0.267)
Score (0-32) restricted^2,unadjusted	23.806	-0.916 (1.297)	-1.024 (1.384)	0.108 (0.983)
Adjusted, baseline outcome only		0.354 (0.505)	-0.227 (0.540)	0.580 (0.439)
Adjusted, baseline outcome & covariates		0.265 (0.457)	-0.419 (0.429)	0.684 (0.407)
Adjusted with entropy weighting		0.314 (0.439)	-0.299 (0.427)	0.613 (0.398)

Notes: The table reports endline means for the control (Arm 3) in column 1 and the estimated ITT effect for each intervention arm (Arm 1 and Arm 2) relative to the control (Arm 3) in columns 2–3. Column 4 compares the estimates for Arm 1 and Arm 2. For example, the unadjusted estimate in column 4 for ‘Passed paragraph’ (0.118) is the difference between the estimate for Arm 1 (0.036) in column 2 and the estimate for Arm 2 (-0.082) in column 3. Minor differences are due to rounding. Numbers in parenthesis indicate robust standard errors. N = 1,178 unless otherwise noted. Regressions were estimated with standard errors adjusted for 36 clusters in schools. Adjusted regressions included controls for the outcome measured at baseline and the following baseline covariates: non-verbal reasoning score, district, age, speaks English at home, ever repeated a grade, mother alive/co-resident status, father alive/co-resident status, mother’s education, father’s education, books in the household (other than textbooks), count of household items, ever used a cell phone, and student-teacher ratio. The adjusted regressions with entropy weighting reweight observations using the weights generated with entropy balancing.

¹Baseline score imputed if multiple choice was not administered, regressions include a binary control variable for imputed score.

²Among participants for whom the multiple choice was administered at baseline, N = 621.

*** p<0.001, ** p<0.01, * p<0.05, † p<0.1

Table 5 Summary of numeracy and non-verbal reasoning results at endline

	(1)	(2)	(3)	(4)
	Control Arm 3 Endline mean	Safe spaces+ e-reader Arm 1 Coefficient (Robust SE)	Safe spaces only Arm 2 Coefficient (Robust SE)	Arm1 vs Arm 2 Coefficient (Robust SE)
UWEZO numeracy
Passed all – scored 7 (=1),unadjusted	0.728	0.055 (0.042)	-0.048 (0.054)	0.103† (0.052)
Adjusted, baseline outcome only		0.024 (0.035)	-0.041 (0.035)	0.065† (0.037)
Adjusted, baseline outcome & covariates		0.033 (0.030)	-0.022 (0.029)	0.055† (0.027)
Adjusted with entropy weighting		0.040 (0.031)	-0.005 (0.031)	0.045† (0.026)
Score (0-7), unadjusted	6.425	0.123 (0.106)	-0.098 (0.136)	0.221† (0.124)
Adjusted, baseline outcome only		0.065 (0.073)	0.005 (0.068)	0.059 (0.063)
Adjusted, baseline outcome & covariates		0.066 (0.056)	0.021 (0.057)	0.045 (0.044)
Adjusted with entropy weighting		0.092 (0.062)	0.069 (0.062)	0.023 (0.045)
Multiple choice numeracy
Score (0-23), unadjusted	11.148	0.189 (0.771)	-1.141 (1.010)	1.330 (0.852)
Adjusted, baseline outcome only^1		-0.007 (0.404)	-0.426 (0.398)	0.419 (0.356)
Adjusted, baseline outcome & covariates^1		-0.219 (0.217)	-0.465 (0.282)	0.246 (0.205)
Adjusted with entropy weighting^1		-0.175 (0.239)	-0.267 (0.322)	0.092 (0.239)
Score (0-23) restricted^2, unadjusted	12.415	-0.027 (0.664)	-0.805 (0.772)	0.778 (0.596)
Adjusted, baseline outcome only		-0.065 (0.371)	-0.560 (0.389)	0.495 (0.339)
Adjusted, baseline outcome & covariates		-0.244 (0.208)	-0.587* (0.277)	0.343 (0.214)
Adjusted with entropy weighting		-0.197 (0.221)	-0.423 (0.307)	0.226 (0.236)
Non-verbal reasoning
Score (0-16), unadjusted	10.443	0.546 (0.468)	-0.286 (0.572)	0.832† (0.450)
Adjusted, baseline outcome only		0.468*(0.190)	-0.042 (0.229)	0.510** (0.173)
Adjusted, baseline outcome & covariates		0.363* (0.163)	-0.023 (0.172)	0.386* (0.160)
Adjusted with entropy weighting		0.331† (0.174)	0.051 (0.193)	0.281 (0.167)

Notes: The table reports endline means for the control (Arm 3) in column 1 and the estimated ITT effect for each intervention arm (Arm 1 and Arm 2) relative to the control (Arm 3) in columns 2–3. Column 4 compares the estimates for Arm 1 and Arm 2. Minor differences are due to rounding. Numbers in parenthesis indicate robust standard errors. N = 1,178 unless otherwise noted. Regressions were estimated with standard errors adjusted for 36 clusters in schools. Adjusted regressions included controls for the outcome measured at baseline and the following baseline covariates: passed UWEZO paragraph, non-verbal reasoning score, district, age, speaks English at home, ever repeated a grade, mother alive/co-resident status, father alive/co-resident status, mother’s education, father’s education, books in the household (other than textbooks), count of household items, ever used a cell phone, and student-teacher ratio. The adjusted regressions with entropy weighting reweight observations using the weights generated with entropy balancing.

¹Baseline score imputed if multiple choice was not administered, regressions include a binary control variable for imputed score.

²Among participants for whom the multiple choice was administered at baseline, N = 959.

*** p<0.001, ** p<0.01, * p<0.05, † p<0.1

Table 6 Summary of results at endline by passed UWEZO paragraph at baseline

	(1)	(2)	(3)	(4)
	Control Arm 3 Endline mean	Safe spaces+ e-reader Arm 1 Coefficient (Robust SE)	Safe spaces only Arm 2 Coefficient (Robust SE)	Arm1 vs Arm 2 Coefficient (Robust SE)
UWEZO literacy
Passed all – scored 6 (=1)
Did not pass UWEZO paragraph at baseline (N=557)	0.180	0.027 (0.037)	-0.038 (0.034)	0.064 (0.039)
Passed UWEZO paragraph at baseline (N=621)	0.861	0.058 (0.042)	0.035 (0.037)	0.023 (0.039)
Difference		0.031 (0.053)	0.073 (0.056)	-0.041 (0.054)
UWEZO numeracy
Passed all – scored 7 (=1)
Did not pass UWEZO paragraph at baseline (N=557)	0.528	0.022 (0.046)	-0.045 (0.045)	0.067 (0.049)
Passed UWEZO paragraph at baseline (N=621)	0.905	0.013 (0.027)	-0.025 (0.033)	0.038 (0.026)
Difference		-0.009 (0.048)	0.020 (0.054)	-0.029 (0.056)
Non-verbal reasoning
Score (0-16)
Did not pass UWEZO paragraph at baseline (N=557)	8.713	0.767** (0.234)	0.040 (0.204)	0.727*** (0.185)
Passed UWEZO paragraph at baseline (N=621)	11.975	-0.111 (0.179)	-0.118 (0.200)	0.007 (0.198)
Difference		-0.878** (0.289)	-0.158 (0.270)	-0.720** (0.226)

Notes: The table reports endline means for the control (Arm 3) in column 1 and the estimated ITT effect for each intervention arm (Arm 1 and Arm 2) relative to the control (Arm 3) in columns 2–3. Column 4 compares the estimates for Arm 1 and Arm 2. Minor differences are due to rounding. Numbers in parenthesis indicate robust standard errors. Regressions included controls for the following baseline covariates: non-verbal reasoning score, district, age, speaks English at home, ever repeated a grade, mother alive/co-resident status, father alive/co-resident status, mother’s education, father’s education, books in the household (other than textbooks), count of household items, ever used a cell phone, and student-teacher ratio. Regressions for UWEZO numeracy also controlled for the outcome measured at baseline. Difference refers to the interaction term between arm and passed UWEZO paragraph at baseline from regressions using the full sample that included interactions between all covariates and passed UWEZO paragraph at baseline. Regressions were estimated with standard errors adjusted for 36 clusters in schools.

*** p<0.001, ** p<0.01, * p<0.05, † p<0.1

Table 7. The effect of attendance on UWEZO literacy and non-verbal reasoning at endline: ANCOVA models for each intervention arm separately^a

		UWEZO Passed all (scored 6)		Non-verbal reasoning score (0–16)
		Coefficient (Robust SE)		Coefficient (Robust SE)
Arm 1 – e-reader
	≤12 sessions (ref)
	13–15 sessions	−0.007 (0.067)		0.191 (0.361)
	16–17 sessions	0.069 (0.064)		−0.380 (0.381)
	18–19 sessions	0.160* (0.061)		−0.348 (0.367)
	Joint test: F	3.53*		1.28
	Number of observations	374		374
Arm 2 – safe spaces only
	≤12 sessions (ref)
	13–15 sessions	−0.013 (0.047)		0.548 (0.337)
	16–17 sessions	−0.047 (0.047)		0.701* (0.331)
	18–19 sessions	0.029 (0.048)		0.772* (0.309)
	Joint test: F	0.94		2.40†
	Number of observations	425		425

**p <.01; *p <.05; †p <.1

^aLinear regressions with robust standard errors adjusted for 36 clusters in schools. Models control for the outcome at baseline and the following baseline covariates: district, age, cognitive score, speaks English at home, ever repeated a grade, mother alive/co-resident status, father alive/co-resident status, mother’s education, father’s education, books in the household (other than textbooks), count of household items, ever used a cell phone, and student–teacher ratio.

Table 8. Interaction of attendance with UWEZO literacy and non-verbal reasoning at endline ANCOVA models^a

	UWEZO Passed all (scored 6)		Non-verbal reasoning score (0–16)
	Coefficient (Robust SE)		Coefficient (Robust SE)
Arms 1 & 2 only
Arm1	0.019 (0.062)		1.070** (0.362)
13–15 sessions	−0.016 (0.045)		0.484* (0.173)
16–17 sessions	−0.046 (0.065)		0.617 (0.366)
18–19 sessions	0.046 (0.045)		0.763* (0.335)
13–15 sessions*arm1	−0.005 (0.072)		−0.313 (0.463)
16–17 sessions*arm1	0.089 (0.084)		−1.033† (0.504)
18–19 sessions*arm1	0.095 (0.086)		−1.151* (0.409)
Joint test: F	2.3†		4.11**
Number of Observations	799		799

**p <.01; *p <.05; †p <.1. ^aLinear regressions with robust standard errors adjusted for 36 clusters in schools. Models control for the outcome at baseline and the following baseline covariates: district, age, cognitive score, speaks English at home, ever repeated a grade, mother alive/co-resident status, father alive/co-resident status, mother’s education, father’s education, books in the household (other than textbooks), count of household items, ever used a cell phone, and student–teacher ratio.

Table A1. GirlsRead! sample flow chart

Enrolment
		Public Schools: 353 schools
		- Lusaka: 268 schools
		- Ndola: 41 schools
		- Chingola: 44 schools
		Purposively selected^a: 45 schools
		- Lusaka^b: 22 schools
		- Ndola: 14 schools
		- Chingola: 9 schools
		Purposively selected^c: 36 schools
		- Lusaka: 15 schools
		- Ndola: 12 schools
		- Chingola: 9 schools
		Rosters of incoming Grade 7 students
		- Lusaka
		15 schools with 50+ girls (38 girls randomly selected)
		0 schools with fewer than 50 girls (all girls selected)
		- Ndola
		10 schools with 50+ girls (38 girls randomly selected)
		2 schools with fewer than 50 girls (all girls selected)
		- Chingola
		3 schools with 50+ girls (38 girls randomly selected)
		6 schools with fewer than 50 girls (all girls selected)^d
		Selected girls: 1364 girls
		- Lusaka: 570 girls
		- Ndola: 452 girls
		- Chingola: 342 girls
Randomised allocation at school level		Arm 1 safe spaces + e-reader (12 schools)	Arm 2 safe spaces^b (12 schools)	Arm 3 control (12 schools)	Total (36 schools)
Baseline survey (January-March 2017)
	Target sample: N	439	483	442	1364
	Non-response: %	4.8%	4.8%	4.8%	4.8%
	Completed: N	418	460	421	1299
	Mean number of girls per school	34.8	38.3	35.1	36.1
	[min,max]	[23,41]	[33,56]	[20,43]	[20,56]
Post-intervention survey (October-November 2017)
	Target sample^b N	418	460	421	1299
	Loss to follow-up: %	3.3%	3.9%	2.4%	3.2%
	Reasons for loss to follow-up
	Refusal: N	6	5	2	13
	Deceased: N	0	1	0	1
	Not located/moved: N	4	7	5	16
	Other/no information: N	4	5	3	12
	Completed^f N	404	442	411	1257
	Mean number of girls per school	33.7	36.8	34.3	34.9
	[min,max]	[22,39]	[30,54]	[19,42]	[19,54]
Endline survey (March–May 2018)
	Target sample^g N	418	459	421	1298
	Loss to follow-up: %	10.5%	7.0%	10.0%	9.1%
	Reasons for loss to follow-up
	Refusal: N	4	4	2	10
	Incapable physically or mentally: N	0	0	1	1
	Not located/moved: N	31	20	31	82
	Other/no information: N	9	8	8	25
	Completed^h N	374	425	379	1178
	Mean number of girls per school	31.2	35.4	31.6	32.7
	[min,max]	[16,38]	[28,51]	[17,37]	[16,51]

^aWe purposively selected schools with Grade 7 in Lusaka, Chingola, and Ndola, the 3 districts specified for Zambia by the DREAMS Innovation Challenge. In coordination with USAID, we aimed to minimise overlap with other DREAMS activities: we excluded DREAMS core schools and Zambia Centre for Communication Programmes (ZCCP) schools in Ndola and Chingola (in which Girls Leading Our World (GLOW) camps were being conducted).

^bWe attempted to get data on 23 schools in Lusaka, but were unable to get data on one, resulting in 22 schools in the sampling frame.

^cWe then visited each school and gathered data on the age of Grade 7 girls. Ndola and Chingola schools listed the ages of girls from the school census (conducted mid-year in April). Lusaka schools listed the ages of girls from the school census or exam entry lists (Grade 7 exams are conducted in October). For each district, we ranked schools by the proportion of girls aged 15 and older. We then selected the 15 schools with the highest proportion of such girls in Lusaka and the 12 schools with the highest proportion of such girls in Ndola.

^dPer roster provided prior to fieldwork, one school had fewer than 50 girls so we planned to invite all of them to participate. When the field team arrived they discovered there were 56 girls, all of whom were thus invited to participate.

^eTarget sample for immediate post-intervention survey was all girls interviewed at baseline.

^f55 girls not interviewed at baseline were also interviewed at the post-intervention survey (e.g. additional programme participants), but were not included in this analysis.

^gTarget sample for endline was all alive girls interviewed at baseline.

^hData from 2 girls in arm 2 who were interviewed at baseline were not included in the analysis. 48 girls not interviewed at baseline were also interviewed at endline (e.g. additional programme participants), but were not included in this analysis.

Table A2. Baseline means for the full baseline sample, by arm

Baseline characteristic/assessment	Total (N = 1299)	Arm 1 safe spaces + e-reader (N = 418)	Arm 2 safe spaces (N = 460)	Arm 3 control (N = 421)	P-value joint test
Age at last birthday	12.9 (SD 1.3)	12.8 (SD 1.3)	12.9 (SD 1.3)	12.9 (SD 1.3)	0.923
English spoken at home	25%	27%	23%	24%	0.830
Ever repeated a grade	35%	34%	35%	37%	0.799
Count of household items (0–15)	8.0 (SD 2.8)	8.5 (SD 2.5)	7.9 (SD 2.9)	7.7 (SD 3.0)	0.306
Mother’s education < junior secondary^a	36%	34%	36%	37%	0.914
Mother’s education: don’t know	19%	19%	16%	21%	0.362
Father’s education < junior secondary^a	14%	15%	14%	14%	0.980
Father’s education: don’t know	29%	28%	27%	31%	0.554
Mother not alive	10%	9%	11%	10%	0.261
Mother not coresident	26%	28%	22%	30%	0.131
Father not alive	22%	21%	18%	29%	0.001
Father not coresident	30%	32%	30%	28%	0.407
No books at household	31%	27%	34%	34%	0.365
1–5 books at household	34%	35%	34%	34%	0.950
6+ books at household
Ever used a cell phone	51%	54%	48%	51%	0.801
Passed UWEZO paragraph^b	53%	59%	47%	53%	0.343
Passed UWEZO story^c	44%	48%	39%	45%	0.519
Passed all UWEZO literacy (scored 6)	38%	41%	34%	40%	0.629
UWEZO literacy score (0–6)	3.4 (SD 2.2)	3.7 (SD 2.2)	3.2 (SD 2.2)	3.5 (SD 2.2)	0.472
Literacy multiple choice score^d (0–32)	13.7 (SD 6.6)	13.8 (SD 6.3)	13.1 (SD 6.5)	14.1 (SD 7.0)	0.777
Passed all UWEZO numeracy (scored 7)	63%	69%^†	60%	61%	0.084
UWEZO numeracy score (0–7)	6.2 (SD 1.4)	6.3 (SD 1.3)	6.0 (SD 1.5)	6.2 (SD 1.3)	0.293
Numeracy multiple choice score^d (0–23)	8.5 (SD 4.7)	8.9 (SD 4.6)	7.9 (SD 4.7)	8.7 (SD 4.7)	0.436
Non-verbal reasoning score^e (0–16)	8.8 (SD 3.3)	9.1 (SD 3.2)	8.5 (SD 3.4)	8.9 (SD 3.2)	0.656
Student-teacher ratio	33 (SD 17)	29 (SD 14)	35 (SD 15)	35 (SD 21)	0.489
District: Lusaka
District: Ndola	34%	35%	32%	35%	0.982
District: Chingola	26%	23%	30%	23%	0.913

P-values from F tests for differences across arms accounting for clustering at the school level to test for baseline balance.

^†p < .1 difference Arm 1 vs Arm 3

^a<Junior secondary is equivalent to ≤ 8 years of schooling

^bPassing the paragraph indicates the respondent could read letters, read simple words and read a paragraph out loud containing 3 simple sentences and 20–22 words and make 2 or fewer mistakes.

^cPassing the story indicates the respondent could do all components listed in ‘a’ plus could read a two paragraph 12 sentence story out loud and make 4 or fewer mistakes.

^dScores were imputed for girls who did not pass the UWEZO

^eNon-verbal reasoning score is the total number of correct answers to 16 items from Raven’s Coloured Progressive Matrices.