The research, led by Tanutchapon Charatcharungkiat and Suppanut Sriutaisuk of the Faculty of Psychology at Chulalongkorn University in Bangkok, together with Hanjoe Kim of Yonsei University in Seoul, set out to adapt and validate the short-form Health Psychological Capital Questionnaire, abbreviated H-PCQ-12, for Thai-language use and to assess how the instrument behaves across cultural boundaries. The motivation is straightforward but consequential: although psychological capital has been studied extensively and applied in workplaces, clinics, and community settings around the world, very few validated non-English instruments exist for measuring this construct, particularly in its health-specific form. Without well-validated local-language tools, researchers in many countries are left either to rely on translations of untested quality or to exclude psychological resources from their studies altogether.

To put the questionnaire through its paces, the team conducted two studies involving three separately recruited samples of adults aged 18 to 40 years, all recruited through online surveys. Study 1 included 323 participants from Thailand and 295 from the United States, allowing the researchers to examine the questionnaire’s factor structure and reliability in each country and, critically, to test whether the instrument measures the same psychological construct in both cultural contexts. Within the Thai sample, the researchers also examined how H-PCQ-12 scores relate to external measures of related constructs. Study 2 then involved a separately recruited Thai sample of 214 participants to replicate the factor-structure and reliability findings and to confirm selected evidence of validity in an independent group, a design feature that strengthens confidence in the results beyond what a single sample can provide.

The statistical heart of the study lies in confirmatory factor analysis, a technique that tests whether patterns of responses to questionnaire items conform to a theorized underlying structure. The researchers evaluated a second-order factor model, an elegant arrangement in which responses reflect four distinct first-order domains—hope, efficacy, resilience, and optimism—that themselves converge on a single higher-order Health PsyCap factor. Across all three samples, this hypothesized model demonstrated generally acceptable to excellent fit to the data, suggesting that the twelve-item questionnaire genuinely captures the architecture that health psychological capital theory predicts. In practical terms, someone’s individual answers about hoping for good health, believing in their ability to stay well, recovering from illness, and expecting positive outcomes can be meaningfully summarized as one overall reservoir of health-related psychological strength.

Reliability, the degree to which a questionnaire produces consistent measurements, also held up well. The H-PCQ-12 total score showed good to excellent internal consistency across all three samples, meaning that respondents who score high on some items tend to score high on the others, as a coherent unidimensional summary score requires. For clinicians and researchers, this matters because a measure that yields erratic scores cannot support meaningful conclusions about individuals or groups. The replication of these reliability findings in a second, independently recruited Thai sample adds a further layer of assurance that the results are not a statistical fluke of one particular group of respondents.

Validity evidence came from several converging lines of analysis using Pearson correlations, which quantify the strength of associations between different measures. The questionnaire showed positive associations with other psychological capital measures, providing convergent validity evidence that it is indeed tapping the same underlying resource that related instruments assess. The team also documented positive associations between H-PCQ-12 scores and quality of life as well as health behaviors, offering evidence based on relations with health-related variables—precisely the pattern one would expect if the questionnaire measures psychological resources for managing health challenges. Intriguingly, the instrument showed only weaker correlations with sense of humor, a construct that might superficially seem related to positive psychology but is theoretically distinct, and this weaker association provided discriminant validity evidence that the questionnaire is not simply measuring positivity in general.

Perhaps the most scientifically demanding part of the study was the analysis of measurement invariance, the statistical test of whether a questionnaire functions equivalently in different groups. The researchers used multigroup models to compare the Thai and U.S. samples at successive levels of stringency. Metric invariance, which requires that the items relate to the underlying construct with the same strength in both cultures, was supported, meaning the questionnaire measures the same construct in Thailand and the United States. However, scalar invariance, the stricter condition needed to make direct numerical comparisons of raw scores across countries, was not supported. In other words, the Thai-language H-PCQ-12 is a valid tool for measuring Health PsyCap within Thailand, and its structure matches the American version, but researchers should be cautious before declaring that a Thai score of a given magnitude means exactly the same thing as the same score in a U.S. sample.

The failure of scalar invariance is a nuanced but honest finding, and it illustrates why cross-cultural validation is so much more than translation. Differences in how people from different cultural backgrounds use rating scales—for instance, in their willingness to endorse extreme response options or in culturally shaped norms around expressing confidence and optimism—can shift how items are interpreted even when the underlying construct is shared. By establishing metric invariance, the study shows that Health PsyCap exists as the same four-part psychological resource in both countries and that the questionnaire tracks it faithfully within each language. By declining to claim scalar invariance, the authors model the kind of restraint that good psychometric science requires: a tool can be excellent for within-country research even when cross-country score comparisons demand additional caution.

The practical implications extend well beyond psychometrics. Health psychological capital is increasingly seen as a modifiable target for intervention, distinct from fixed traits, with programs designed to build hope, efficacy, resilience, and optimism in patients managing chronic illness and in populations facing public health challenges. A brief twelve-item measure that can be administered online in minutes opens the door for Thai researchers and practitioners to screen individuals, evaluate interventions, and include psychological resources in large-scale health studies that were previously inaccessible to rigorous measurement. Given that Southeast Asian populations have historically been underrepresented in psychological instrument development, a validated Thai version represents a tangible contribution to democratizing health psychology research.

The study was reviewed and approved by the Research Ethics Review Committee for Research Involving Human Research Participants, Group I, at Chulalongkorn University, and was conducted in accordance with the Belmont Report, the Declaration of Helsinki, and related international guidelines. The research was supported by Chulalongkorn University’s Second Century Fund and by the East West Psychological Science Research Center in the university’s Faculty of Psychology. The authors declare no competing interests. For now, the conclusions the team draws are measured and precise: the H-PCQ-12 scores demonstrated adequate reliability, and the findings provide validity evidence supporting their interpretation among Thai adults. With replication in an independent sample, strong internal consistency, convergent and discriminant evidence, and partial but meaningful cross-cultural invariance, this small questionnaire takes a significant step toward letting health psychological capital research speak more languages than one.

Subject of Research: Cross-cultural psychometric validation of the short-form Health Psychological Capital Questionnaire in Thai and U.S. adults

Article Title: The short-form health psychological capital questionnaire: psychometric validation and measurement invariance across Thailand and the United States

Article References: Charatcharungkiat, T., Kim, H., & Sriutaisuk, S. (2026). The short-form health psychological capital questionnaire: psychometric validation and measurement invariance across Thailand and the United States. BMC Psychology. https://doi.org/10.1186/s40359-026-05636-6

Image Credits: AI Generated

DOI: 10.1186/s40359-026-05636-6

Keywords: Health Psychological Capital, psychometrics, questionnaire validation, measurement invariance, Thailand, United States, confirmatory factor analysis, positive psychology, hope, resilience, self-efficacy, optimism