Validity and Reliability Assessment of Attitude Scales for Hepatitis B Vaccination Among Parents in Ho Chi Minh City, Vietnam

Figures & data

Figure 1 Mixed methods design: Qualitative (N= 56) and quantitative (N=768) strands with data collection and analysis procedures.

Abbreviations: FGDs, Focus Group Discussions; HBM, Health Belief Model; CVI, Content Validity Index; RA, Reliability Analysis; EFA, Exploratory Factor Analysis; CFA, Confirmatory Factor Analysis.

Table 1 Sex, Age, and Education of Participants (N=768)

	Total (N=768)	RA and EFA (n=192)	CFA (n=576)	p
Sex
Male	146 (19.0)	43 (22.4)	103 (17.9)	0.171*
Female	621 (81.0)	149 (77.6)	472 (82.1)
Education
Pre-primary education	20 (2.6)	3 (1.6)	17 (3.0)	Reference
Primary education	96 (12.5)	30 (16.6)	66 (11.5)	0.154^#
Secondary education	592 (77.2)	141 (73.4)	451 (78.4)	0.367^#
Post-secondary education	59 (7.7)	18 (9.4)	41 (7.1)	0.185^#
Age (Mean ± SD)	30.8 ± 5.1	30.5 ± 4.7	30.9 ± 5.2	0.370^#

Notes: *Chi-square test; ^#Logistic regression.

Table 2 Internal Consistency Reliability of the Attitude Scales Towards Hepatitis B Vaccination (N=192)

Item	Sign	Original Scale			Modified Scale
		Item-Test Corr.	Item-Rest Corr.	Alpha	Item-Test Corr.	Item-Rest Corr.	Alpha
1. My child is at high risk for Hepatitis B	+	0.508	0.330	0.693	0.553	0.367	0.721
2. I think my child will get Hepatitis B in future	+	0.621	0.498	0.667	0.656	0.529	0.694
3. My child could be very sick if she/he got HBV	+	0.603	0.499	0.671	0.610	0.497	0.702
4. I am afraid to even think about my child getting sick with HBV	+	0.531	0.403	0.682	0.543	0.405	0.713
5. Immunization will prevent my child from catching HBV	+	0.603	0.519	0.674	0.631	0.544	0.701
6. By being immunized and not getting HBV, my child will be protecting others from HBV	+	0.475	0.324	0.692	0.475	0.311	0.727
7. Need to get the Hepatitis B vaccination on schedule to prevent my child from getting HBV	+	0.491	0.376	0.686	0.519	0.398	0.715
8. The Hepatitis B vaccine can cause AEFIs	-	0.436	0.287	0.697	0.455	0.294	0.728
9. The Hepatitis B shot can be painful	-	0.383	0.190	0.715	0.381	0.172	0.754
10. It is an inconvenient time to take my child in for vaccines	-	0.537	0.433	0.681	0.523	0.408	0.714
11. That is an inconvenient location to take my child in for vaccines	-	0.573	0.476	0.677	0.578	0.473	0.707
12. Hepatitis B is a dangerous disease	+	0.289	0.167	0.709	Excluded
13. Watching my child get needles frightens me	+	0.288	0.082	0.733	Excluded
Total				0.708	0.735

Table 3 Exploratory Factor Analysis for Attitude Scales Towards Hepatitis B Vaccination (N=192)

Item	Factors
	1	2	3	4
1. My child is at high risk for Hepatitis B	0.880	−0.091	0.064	−0.106
2. I think my child will get Hepatitis B in future	0.573	0.282	0.035	−0.063
3. My child could be very sick if she/he got HBV	0.653	0.130	0.117	0.121
4. I am afraid to even think about my child getting sick with HBV	0.683	−0.211	−0.176	0.083
5. Immunization will prevent my child from catching HBV	0.182	0.332	−0.095	0.266
6. By being immunized and not getting HBV, my child will be protecting others from HBV	−0.037	0.890	0.082	−0.148
7. Need to get the Hepatitis B vaccination on schedule to prevent my child from getting HBV	−0.113	0.605	−0.023	0.282
8. The Hepatitis B vaccine can cause AEFIs	−0.046	−0.288	0.626	0.164
9. The Hepatitis B shot can be painful	0.078	0.158	0.874	−0.069
10. It is an inconvenient time to take my child in for vaccines	−0.063	−0.050	0.038	0.927
11. That is an inconvenient location to take my child in for vaccines	0.021	−0.064	−0.029	0.886
Eigenvalue	3.34	1.42	1.05	1.01
Explained variance	30.4%	13.0%	9.5%	9.2%
Cumulative of explained variance	62.1%

Figure 2 Confirm factor analysis for Attitude Scales towards Hepatitis B Vaccination (N=576).

Notes: Oval, Endogenous variable; Value in oval, Standardized variance; Rectangle, Exogenous variables; Value in rectangle, intercept; ɛ, random errors; Value on one-way arrows are standardized factor loading; Value on two-way arrows show Covariances.

Table 4 Fit Statistic for CFA Model (N=576)

Fit Statistic	Value	Expected Value
Likelihood ratio test for model vs saturated comparison
Χ^2(38)	114.33
p-value	<0.001	>0.05
Likelihood ratio test for baseline vs saturated comparison
Χ^2(55)	1025.40
p-value	<0.001	>0.05
Population error
Root mean square error of approximation (RMSEA)	0.059	<0.08
RMSEA 90% CI, lower bound	0.047
RMSEA 90% CI, upper bound	0.072	<0.08
pclose	0.109
Baseline comparison
Comparative fit index (CFI)	0.921	>0.9
Tucker-Lewis index (TLI)	0.886	Close to 1
Size of residuals
Standardized root mean squared residual (SRMR)	0.039	<0.08
Coefficient of determination (CD)	0.984	Close to 1