Health insurance and hospitalisation duration: empirical evidence from Ghana’s national health insurance scheme

Figures & data

Table 1. Variables, measurement and descriptive statistics.

Variable	Measurement	Obs	Mean	SD
Dependent variable
Hospitalisation	Continuous: number of hospitalisation days	862	6.4612	14.509
Independent variables
NHIS enrolment	Dummy: 1 = currently insured; 0 = otherwise	19,247	0.615	0.487
Gender	Dummy: 1 = male; 0 = otherwise	19,247	0.479	0.500
Age	Continuous: positive whole numbers in years	19,247	35.721	20.108
Age squared	Continuous: positive whole numbers of square of age	19,247	1680.313	1723.330
Education	Ordinal: measured on a five-point scale ranging from 0 for no formal education to 4 as the highest educational level attained	19,247	0.492	0.834
Locality (urban)	Dummy: 1 = resides in urban area; 0 = otherwise	19,247	0.3412	0.474
Fever	Dummy: 1 = if suffered Fever; 0 = otherwise	19,247	0.060	0.237
Chronic illness	Dummy: 1 = if exposed to chronic illness (sores, irritations and/or numbness); 0 = otherwise	19,247	0.325	0.468
Physical inactivity	Dummy: 1 = difficulty in participating in physical activities/roles; 0 = otherwise	19,247	0.139	0.346
Self-assessed health	Ordinal: unhealthy =1, somewhat unhealthy =2, somewhat healthy =3 and Very healthy =4	19,247	3.678	0.6108
Average household expenditure	Continuous: positive numbers in Ghana cedis (i.e. monthly household expenditure divided by household size)	19,247	149.908	178.856
Instrumental variable
Formal-sector work	Dummy: 1 = if household head is a formal-sector worker; 0 = otherwise	19,247	0.107	0.309

SD: standard deviation; Obs.: observation.

Table 2. Results of the endogenous switching regression model for count data outcome.

		Hospitalisation days
Variable	NHIS enrolment	Uninsured	Insured
Gender	−0.313***	0.131	0.415***
	(0.107)	(0.146)	(0.053)
Age	0.010***	−0.049***	0.029***
	(0.003)	(0.007)	(0.007)
Age squared	−	0.001***	−0.0004***
	−	(0.0001)	(0.0001)
Education	−0.039	−0.105	−0.107***
	(0.074)	(0.091)	(0.022)
Chronic illness	−0.003	0.327***	−0.009
	(0.101)	(0.085)	(0.059)
Physical inactivity	0.148	−0.312	0.530***
	(0.138)	(0.207)	(0.085)
Average household expenditure	−0.000	−0.001*	0.001***
	(0.000)	(0.000)	(0.000)
Self-assessed health	−	−0.571***	−0.317***
	−	(0.141)	(0.041)
Fever	−	0.100	−0.109
	−	(0.171)	(0.085)
Locality (urban)	−	0.165	0.043
	−	(0.134)	(0.058)
Formal-sector work	0.302**	−	−
	(0.150)	−	−
Constant	0.290**	4.635***	1.845***
	(0.147)	(0.610)	(0.180)
Lambda	−	0.612***	−0.543***
	−	(0.078)	(0.082)
Observations	827
Wald ${\chi }^2$	1,136.81***
Log pseudolikelihood	−2,643.051

Robust standard errors in parentheses; *p < .1, **p < .05, ***p < .01.

Table 3. Estimates of the treatment effects of NHIS enrolment on hospitalisation days.

Effect	Estimate	Standard error	z
ATE	−5.129***	1.583	−3.240
ATT	−8.321***	1.602	−5.194
ATU	5.934***	1.006	5.899

ATE: Average Treatment Effect; ATT is the average effect of the treatment on the treated and ATU is the average effect of the treatment on the untreated; ***p < .01.

Table A1. Pearson correlation coefficient analysis for testing the instrument’s validity.

Instrumental variable	Dependent variable	Correlation coefficient	p-value
Formal-sector work	NHIS enrolment	0.1280	.0000
Formal-sector work	Hospitalisation days	0.0063	.8540

Table A2. Logit estimation for NHIS membership and negative binomial regression estimation for hospitalisation days.

	NHIS membership	Hospitalisation days
Variable	Coefficient	Coefficient
Formal-sector work	0.816***	0.095
	(0.059)	(0.116)
Gender	−0.580***	0.472***
	(0.031)	(0.074)
Age	−0.000	0.009
	(0.001)	(0.007)
Age squared	−	−0.000*
	−	(0.000)
Education	0.248***	0.034
	(0.022)	(0.047)
Chronic illness	−0.079**	0.105
	(0.034)	(0.074)
Physical inactivity	0.590***	0.204**
	(0.048)	(0.098)
Average household expenditure	0.000***	0.001**
	(0.000)	(0.000)
Self-assessed health	−	−0.412***
	−	(0.053)
Fever	−	−0.099
	−	(0.110)
Locality (urban)	−	−0.029
	−	(0.073)
Constant	0.445***	2.620***
	(0.037)	(0.266)
Lnalpha	−	−0.180***
	−	(0.052)
Alpha	−	0.835***
	−	(0.043)
Observations	19,247	862
LR χ^2	996.37***	163.35***
Log likelihood	−12,332.381	−2,452.232
Pseudo R^2	0.039	0.0322
Model classification	63.07%	−

Standard errors in parentheses; *p < .1, **p < .05, ***p < .01.

Likelihood-ratio test of alpha = 0: chibar2(01) = 5605.11 Prob> =chibar2 = 0.000.

Data availability statement

The data that support the findings of this study are openly available in Harvard Dataverse at https://doi.org/10.7910/DVN/E5QP0F,referencenumberV1,UNF:6:JLtXxepgNXfzyX0ThGLDiw==[fileUNF]