This study aimed to generate psychometric validity evidence for a concise measure of trust in U.S. public health actors specifically for vaccine information. The authors developed a novel 4‑item instrument, named the Public Health Actor Trust for Information about Vaccines (HAT‑IV), intended for use in U.S. population survey research to quantify respondents' trust in institutions and clinicians that provide vaccine information.
Analyses used data from 7,394 respondents to nationally representative Kaiser Family Foundation (KFF) public opinion surveys collected at five time points spanning 2020–2025. The sample and survey design details beyond respondent count and time points are not reported in the abstract provided.
The four items in the scale asked respondents to indicate their level of trust in four sources to provide reliable vaccine information: the U.S. Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC), their local public health department, and their own doctor. The intended latent construct is trust in public health actors for vaccine information.
Using classical test theory, the authors estimated internal consistency reliability for the 4‑item measure. The scale demonstrated high internal consistency with Cronbach's alpha = 0.84, supporting coherent scale scoring. Parallel analysis was used to evaluate dimensionality and indicated a single underlying dimension for the items, consistent with a unidimensional construct of trust in public health actors for vaccine information.
The authors fit an Item Response Theory (IRT) graded response model to evaluate item and scale functioning across the latent trust continuum. IRT results reported that items provided sufficient information across a broad range of latent trust levels. Reported item discrimination (a) parameters ranged from 1.55 to 4.04, indicating moderate to strong discrimination among items. Threshold (b) parameters spanned from -2.62 to 0.69, which suggests the items capture variation from low to moderately high levels of the latent trait.
The study estimated differential test functioning (DTF) at the scale level by political identity (partisanship) and by survey time point. The authors report no substantively meaningful DTF at the scale level for either political partisanship or time point, indicating the scale's functioning was robust across these groups and periods as assessed in their analyses.
The HAT‑IV scale demonstrated expected associations with vaccine‑related outcomes. Higher scale scores were positively associated with vaccine uptake and pro‑vaccine attitudes. Specifically, scale scores were associated with greater confidence in COVID‑19, influenza, and MMR vaccines. These associations were reported as statistically significant (all p < .001) in the abstract.
The authors conclude that the HAT‑IV scale exhibits strong psychometric properties and meaningful associations with vaccine attitudes and behaviors across U.S. political and public health contexts represented in the surveyed periods. Because it is brief and informative, the HAT‑IV is presented as a practical tool to measure individuals' trust in U.S. public health actors for vaccine information in survey research. The scale can be used to study relationships between trust in key public health actors and vaccine outcomes in the U.S.
The abstract states that the authors declared no known competing financial interests or personal relationships that could have influenced the work. The article is published in Vaccine (2026) with DOI 10.1016/j.vaccine.2026.129026 and the record indicates the full text is available via publisher links. Additional methodological specifics, detailed item wording, survey administration procedures, and limitations beyond what is summarized in the abstract were not reported in the provided source.