Abstract

To assess the construct validity and reliability of the Parent Attitudes about Childhood Vaccines survey. Cross-sectional survey of parents of 19–35 month old children in a closed model HMO. We used factor analysis to confirm survey sub-domains and Cronbach's α to determine the internal consistency reliability of sub-domain scales. Construct validity was assessed by linking parental responses to their child's immunization record. Our response rate was 46% (N = 230). Factor analysis identified 3 factors that explained 70% of the total variance for the 18 survey items. We deleted 3 items that failed to load highly (>.4) on an identified factor, correlated poorly with other items, or had a hesitant response that was not associated with increased under-immunization. Cronbach's α coefficients for the 3 sub-domain scales created by grouping the remaining 15 items were .74, .84, and .74, respectively. Children of parents with survey scores of 50–79 had 14% more days under-immunized from birth to 19 months (95% CI: 8.0, 20.5) than those with parents who scored <50. Scores of ≥80 were associated with 51% more days under-immunized (95% CI: 38.2, 63.4). The revised survey is a valid and reliable instrument to identify vaccine-hesitant parents.