Theory of planned behavior explains males’ and females’ intention to receive COVID-19 vaccines differently

Figures & data

Table 1. Descriptive statistics, Cronbach’s α, and bivariate correlations of key variables.

	1	2	3	4
1.Attitudes toward vaccines	-
2.Subjective norms	0.43***	-
3.Perceived behavioral control	0.45***	0.47***	-
4.Intention to receive vaccines	0.33***	0.47***	0.46***	-
M	4.59	4.14	4.08	3.65
SD	0.62	0.75	0.70	1.10
Skewness	−1.62	−0.59	−0.35	−0.64

^a***p < 0.001.

Table 2. The associations between TPB elements and intention to receive vaccines among the overall sample.

	Intention to receive vaccines (R^2 = 0.33)
	B	SE	p	95%CI
Key variables
Attitudes toward vaccines	0.15	0.10	.110	[−0.025, 0.350]
Subjective norms	0.41	0.09	<.001	[0.247, 0.584]
Perceived behavioral control	0.43	0.09	<.001	[0.257, 0.610]
Covariates
Gender^a	−0.01	0.10	.900	[−0.196, 0.185]
Age	0.00	0.01	.526	[−0.007, 0.014]
Education^b	0.08	0.05	.069	[−0.007, 0.168]
Hometown^c	0.07	0.09	.489	[−0.123, 0.246]
Relation with COVID-19^d	−0.18	0.42	.663	[−0.955, 0.787]
History of chronic physical illness^e	0.34	0.19	.076	[−0.023, 0.735]
History of psychiatric illness^f	−0.37	0.38	.326	[−1.074, 0.407]
Current physical health status	0.15	0.06	.018	[0.027, 0.268]

^aGender: 1 = males, 2 = females.

^bEducation: 1 = primary school and below, 2 = middle school degree, 3 = college diploma, 4 = bachelor’s degree; 5 = postgraduate degree.

^cHometown: 1 = urban area, 2 = rural area.

^dRelation with COVID-19: 1 = related, 2 = not related.

^eHistory of chronic physical illness: 1 yes, 2 = no.

^fHistory of psychiatric illness: 1 = yes, 2 = no.

Table 3. Measurement invariance of the TPB measures.

	x^2	df	CFI	ΔCFI	SRMR	RMSEA (90%CI)
Attitudes toward vaccines
M1 Configural invariance	8.815	6	0.999	-	0.012	0.048 [0.000, 0.110]
M2 Metric invariance	9.307	10	1.000	0.001	0.021	0.000 [0.000, 0.072]
M3 Scalar invariance	17.737	14	0.998	−0.002	0.030	0.036 [0.000, 0.081]
Subjective norms
M1 Configural invariance	0.000	0	1.000	-	0.000	0.000 [0.000, 0.000]
M2 Metric invariance	1.877	2	1.000	0	0.042	0.000 [0.000, 0.136]
M3 Scalar invariance	6.628	4	0.995	−0.005	0.055	0.057 [0.000, 0.130]
Perceived behavioral control
M1 Configural invariance	0.000	0	1.000	-	0.000	0.000 [0.000, 0.000]
M2 Metric invariance	6.539	2	0.993	−0.007	0.088	0.106 [0.021, 0.201]
M3 Partial measurement invariance	0.164	1	1.000	0.007	0.015	0.000 [0.000, 0.138]
M4 Scalar invariance	1.929	3	1.000	0	0.027	0.000 [0.000, 0.100]

Table 4. The associations between TPB elements and intention to receive vaccines by gender.

Paths	Males (N = 144)				Females (N = 261)				Comparison
	B	SE	p	95% CI	B	SE	p	95% CI	B	SE	p	95% CI
Att→Int	0.462	0.166	.005	[0.142, 0.785]	0.008	0.106	.942	[−0.199, 0.211]	0.454	0.196	.021	[0.095, 0.860]
SN→Int	0.032	0.187	.862	[−0.340, 0.394]	0.565	0.098	<.001	[0.379, 0.763]	−0.532	0.212	.012	[−0.954, −0.124]
PBC→Int	0.504	0.166	.002	[0.167, 0.823]	0.387	0.103	<.001	[0.197, 0.602]	0.117	0.195	.549	[−0.293, 0.483]

Att: Attitudes toward vaccines.

SN: Subjective norms.

PBC: Perceived behavioral control.

Int: Intention to receive vaccines.

Covariates were controlled for but not shown in the table for simplicity.