Psychological reactance and vaccine uptake: a longitudinal study

Figures & data

Figure 1. Participant flow and attrition. Note. Data quality was assessed by the panel agency Flycatcher via their standard procedure based on open answers, consistency of answers, response time and straight lining.

Table 1. Characteristics of the research sample.

Characteristic	T0 n = 1411	T1 n = 925	T2 n = 1132	Dutch population
Gender
Male	51.10%	52.54%	51.33%	50%
Female	48.90%	47.46%	48.67%	50%
Age in years
18–29	23.88%	20.86%	22.88%	28%
30–39	22.18%	22.92%	22.26%	22%
40–49	25.02%	20.97%	24.20%	24%
50–59	28.84%	35.24%	30.65%	26%
Education level
Low	17.15%	19.03%	17.49%	21%
Middle	45.57%	46.49%	45.23%	46%
High	37.28%	34.49%	37.28%	33%

Note. The education levels are based on the categorisation used by the Dutch Centre for Statistics. Low includes primary school, high school education preparing for vocational college, and the first three years of high school education preparing for bachelor’s degrees. Medium includes finishing high school education preparing for bachelor’s degrees, and vocational college. High includes bachelor’s and master’s education.

Table 2. Factor loadings on confidence, freedom threat and reactance scales.

		Factor loadings
Scale	Item	T0	T1
Confidence	I feel uncertain about the vaccination decision	0.76	0.75
	I know what I’m up for if I get vaccinated*	0.44	0.42
	I find it hard to decide on the best choice for me	0.92	0.92
Freedom Threat	The call threatens my freedom to choose	0.94	0.94
	The call makes me feel like I cannot decide myself	0.93	0.92
	The call is manipulative	0.88	0.90
Reactance	The call annoys me	0.97	0.96
	I am frustrated about the call	0.92	0.91
	I am offended by the call	0.98	0.96

Note. The items are displayed in short form, e.g., ‘the call’ refers to ‘the government’s call to get vaccinated’. The full items are described in the Materials section.

* This item is mirrored. The factor loadings represent the reversed item score.

Table 3. Descriptive statistics of the measured variables at T0, T1 and T2.

Variable	Means			Correlations
	T0: M (SD) n = 1411	T1: M (SD) n = 925	T2: n = 1132	Freedom Threat	Reactance	Vaccination Intention	Decision Confidence
Freedom threat	28.20 (32.35)	28.04 (31.40)		r = .79
Reactance	20.28 (30.29)	20.47 (29.01)		T0: r = .85 T1: r = .86	r = .78
Vaccination intention	77.94 (31.96)	78.84 (33.30)		T0: r = −.67 T1: r = −.66	T0: r = −.66 T1: r = −.67	r = .83
Decision confidence	70.16 (26.59)	72.89 (25.15)		T0: r = −.57 T1: r = −.52	T0: r = −.54 T1: r = −.51	T0: r = .63 T1: r = .56	r = .70
Vaccine uptake (%)	0%	0%	86.13%	rpb = −.76	rpb = −.81	rpb = .99	rpb = .45

Note. Boxes on the diagonal indicate the bivariate correlations between the variable’s measurements at T0 and T1. Correlations with vaccine uptake are point-biserial correlations between continuous variables at T1 and uptake measured at T2. r = Spearman’s rho. All correlations were significant at p < .001.

Figure 2. Indirect effects of reactance on vaccine uptake via vaccination intention. Note. Intention T0 effects on vaccine uptake are reported at high (+1 SD) and low (−1 SD) confidence. The coefficients represent B-weights, and paths to the categorical outcome variable are indicated with odds ratios. Dotted lines indicate included effects of the covariate (intentions at T0). * p < .05, as derived from bootstrapped CIs.

Table 4. Regression table for research question 4.

	Model coefficients for intentions to vaccine uptake
	Outcome
	M (Intentions T1)			Y (Vaccine uptake T2)
Predictor	B	SE	95% CI	OR	95% CI
X (Reactance T0)	−0.05	0.03	[−0.11; 0.01]	1.01	[0.99; 1.03]
X mediated by M (Reactance T0 via Intentions T1)	–	–	–	1.00	[0.99; 1.01]
M (Intentions T1)	–	–	–	1.05	[1.03; 1.08]
Covariate (Intentions T0)	0.87	0.03	[0.81; 0.92]	1.04	[1.01; 1.06]
Constant	15.03	2.71	[9.96; 20.60]	0.02	[0.004, 0.05]
	R² = .83, F(2, 862) = 2134.83, p < .001			Nagelkerke’s R²N = .789, p < .001