Table 4

Results of mixed logit model with main effects and interactions

Attributes	β	SE	P value	95% CI
Non-vaccination	−6.178	0.767	<0.001	−7.680 to −4.675
Protection rate prevented by a vaccine (ref: 70%)
80%	0.940	0.088	<0.001	0.767 to 1.113
90%	1.218	0.235	<0.001	0.758 to 1.679
Risk of serious side effects event (ref: 10/100 000)
2/100 000	1.804	0.116	<0.001	1.576 to 2.031
1/100 000	2.334	0.265	<0.001	1.815 to 2.854
Location of vaccine manufacturer (ref: domestic)
Imported	−0.298	0.079	<0.001	−0.454 to −0.143
Duration of vaccine-induced protection (ref: 6 months)
12 months	0.583	0.065	<0.001	0.456 to 0.711
Cost	−0.001	0.002	0.624	−0.005 to 0.003
Interaction terms
Non-vaccination × age (>30 years old)	2.843	0.778	<0.001	1.319 to 4.367
Non-vaccination × rural	−2.216	0.973	0.023	−4.123 to −1.305
Non-vaccination × father	−0.157	0.746	0.833	−1.620 to −0.302
Non-vaccination × only one child	1.017	0.967	0.293	−0.878 to 2.911
90% protection rate × age (>30 years old)	0.581	0.209	0.005	0.173 to 0.990
90% protection rate × rural	0.732	0.220	0.001	0.302 to 1.163
90% protection rate × education level (college and above)	0.540	0.213	0.011	0.123 to 0.956
90% protection rate × only one child	−0.231	0.216	0.285	−0.655 to 0.192
Lowest risk of serious side effects × only one child	−0.506	0.236	0.032	−0.969 to −0.043
Lowest risk of serious side effects × rural	0.838	0.240	<0.001	0.367 to 1.309
Lowest risk of serious side effects × age (>30 years old)	0.372	0.223	0.096	−0.066 to 0.810
Lowest risk of serious side effects × education level (college and above)	0.291	0.230	0.206	−0.160 to 0.742
Log likelihood	−2631.978
No. of respondents	449
No. of observations	13 446

1. All attributes except for cost were coded for dummy variables.
2. A total of 600 parents enrolled in the survey and 579 completed the majority of the questionnaire at least. Respondents (130) who failed the consistency test were excluded from the main DCE result reported in this table.
3. Interaction terms were treated as fixed effect variables, and the others as random effect variables.
DCE, discrete choice experiment; ref, reference.