Table 2.

Estimation results of willingness to pay models for a COVID-19 vaccine in Ecuador.

Variable	Model 1	Model 2	Model 3
Constant	4.342***	4.260***	3.479***
	(0.112)	(0.392)	(0.545)
Duration of protection	0.259**	0.014**	0.259**
	(0.127)	(0.007)	(0.128)
Efficiency of protection	0.028	0.001	0.053
	(0.127)	(0.005)	(0.127)
Contracting probability			−0.001
			(0.003)
Hospitalized probability			0.006**
			(0.003)
Death probability			0.005
			(0.004)
Age			0.003
			(0.006)
Household size			−0.003
			(0.033)
Income (thousands of dollars)			0.337***
			(0.101)
Gender (Female = 1, Male = 0)			−0.039
			(0.134)
College education (Yes = 1, No = 0)			0.120
			(0.156)
Health insurance (Yes = 1, No = 0)			0.226
			(0.140)
Employment status (Employed = 1, Other = 0)			0.274*
			(0.164)
Knowledge score			0.0002
			(0.038)
Region of residence
Pichincha			−0.300
			(0.183)
Guayas			−0.357*
			(0.213)
Sierra and Amazon			−0.170
			(0.202)
Sigma ($\sigma$)	1.686***	1.686***	1.621***
Sample size	972	972	921
Wald Chi2	4.21	4.21	44.68
P-value (Prob > Chi2)	0.12	0.12	0.0002
Log likelihood	−1156.06	−1156.06	−1059.061

Notes. The parametric model used is a log-normal distribution with parameters $\mu \mathrm{a}\mathrm{n}\mathrm{d}\sigma ,\mu ={\mathit{X}}_{\mathit{i}}\text{'}$β.

Standard errors in parenthesis.

***indicates significance at 1%, ** indicates significance at 5%, and * indicates significance at 10%.