Effect of cash incentives on tetanus toxoid vaccination among rural Nigerian women: a randomized controlled trial

Figures & data

Figure 1. Map of study site, Jada Local Government Area, Adamawa State, Nigeria

Table 1. Demographics of participants by study arm

		Amount of Cash Incentives
	Total (n = 2482)	C5 (n = 765)	C300 (n = 850)	C800 (n = 867)	Difference (joint significance; p-value)
	(1)	(2)	(3)	(4)	(5)
Baseline Characteristics:
Age	25.1 (6.1)	24.9 (6.1)	24.9 (6.1)	25.5 (6.1)	0.092
Religion					0.848
Christian	1230 (49.6%)	399 (52.2%)	404 (47.5%)	449 (51.8%)
Muslim	1252 (50.4%)	366 (47.8%)	446 (52.5%)	418 (48.2%)
Education					0.838
No education	1199 (48.3%)	377 (49.3%)	451 (53.1%)	455 (52.5%)
Any education	1283 (51.7%)	388 (50.7%)	399 (46.9%)	412 (47.5%)
Marital status					0.851
Married	2103 (84.7%)	647 (84.6%)	718 (84.5%)	738 (85.1%)
Single	379 (15.3%)	118 (15.4%)	132 (45.2%)	129 (14.9%)
Pregnancy					0.237
Not pregnant	2036 (82.0%)	639 (83.5%)	700 (82.4%)	697 (80.4%)
Pregnant	446 (18.0%)	126 (16.5%)	150 (17.7%)	170 (19.6%)
Have children					0.925
No	584 (23.5%)	181 (23.7%)	203 (23.9%)	200 (23.1%)
Yes	1898 (76.5%)	584 (76.3%)	647 (76.1%)	667 (76.9%)
Has paid work					0.227
No	1402 (56.5%)	441 (57.7%)	466 (54.8%)	495 (57.1%)
Yes	1080 (43.5%)	324 (42.3%)	384 (45.2%)	372 (42.9%)
Monthly HH earning per capita (naira)	5876 (8156)	5430 (7392)	6080 (8433)	6068 (8509)	0.188
Distance to clinic (km)	1.7 (1.2)	1.7 (1.2)	1.7 (1.2)	1.7 (1.2)	0.989
Transport to clinic (naira)	124 (197)	122 (210)	114 (165)	134 (214)	0.029
Ever used clinic					0.777
No	689 (27.8%)	219 (28.6%)	220 (25.9%)	250 (28.8%)
Yes	1793 (72.2%)	546 (71.4%)	630 (74.1%)	617 (71.2%)
Received tetanus vaccine before					0.620
No	1493 (60.2%)	458 (59.9%)	515 (60.6%)	520 (60.0%)
Yes	989 (39.8%)	307 (40.1%)	335 (39.4%)	347 (40.0%)

Notes: These are based on the analysis sample of 2,482 women. Values are the mean with standard deviation, or the number of respondents in each

category with the proportion (%). Transportation costs for 66 observations are missing. 150 naira = $1 approximately. Column (4) reports the p-value for the joint significance test for the equality of the means.

Figure 2. Effect of cash incentives on Tetanus-toxoid Vaccination

Table 2. Logistic regression analysis of CCT by transportation costs

		Received vaccine (OR [95% CI])
	Transportation costs:
Outcome:	All	zero	≥0 & ≤300 naira	≥ = 300 naira
Sample:	(1)	(2)	(3)	(4)
(Comparison: C5)
C300	3.362***	3.581***	5.770***	1.931*
	[2.595,4.354]	[2.421,5.295]	[3.434,9.695]	[0.976,3.819]
C800	7.575***	7.031***	14.578***	5.831***
	[5.648,10.160]	[4.505,10.974]	[8.119,26.174]	[2.865,11.870]
N	2320	1048	647	274

Notes: These are based on the analysis sample of 2,482 women. The comparison group is C5 (Column 1), C5 with zero transportation costs (Column 2), C5 with 0–300 naira transportation costs (Column 3), and C5 with 300 or more tranportation costs (Column 4). Some observations are dropped after controlling for village fixed effects. Transportation costs are the self-reported transportation costs to visit the clinic (both ways). We control for village fixed effects. *

significant at 10%; ** significant at 5%; *** significant at 1%

Figure 3. Relationship between transportation costs and vaccination

Notes: The effect of transportation costs is estimated using a locally weighted regression.

Table 3. Effects of CCT on transportation to clinic (Endline)

	Mode of transport to clinic
Panel A: Logistic regression on transport mode (odds ratio)Outcome:	Walk(1)	Motorcycle or Car(2)
(Comparison: C5)
C300	0.817	1.336
	[0.562,1.186]	[0.914,1.953]
C800	0.748	1.459**
	[0.520,1.075]	[1.009,2.111]
N	1656	1603
	Time and costs of transportation
Panel B: OLS regression on transport time/costsOutcome:	Transport minutes(3)	Transport costs (naira)4
(Comparison: C5)
C300	−0.891	9.521*
	[-4.358,2.576]	[-0.930,19.972]
C800	-0.351	14.359***
	[-3.721,3.019]	[4.209,24.510]
N	1829	1775
r2	0.515	0.404

Notes: These are based on the sample of 1,829 women who attended the assinged clinic within a week after the intervention. Some observations are dropped after controlling for village fixed effects in Panel A. In Column 4, some observations are dropped because the baseline transportation costs were missing for these dropped observations. Covariates are distance to the health clinic and the same outcome measured at the baseline. We control for village fixed effects. * significant at 10%;

** significant at 5%; *** significant at 1%