The Greek Versions of the HLS19 Health Literacy Instruments (HLS19-NAV-GR, HLS19-COM-GR, and HLS19-VAC-GR): Translation, Cultural Adaptation, and Descriptive Pilot Evaluation

<b>Background</b>: Health literacy (HL) is a key determinant of health outcomes and equity. The European Health Literacy Survey 2019 (HLS₁₉) introduced three domain-specific instruments-HLS₁₉-NAV, HLS₁₉-COM-P-Q11, and HLS₁₉-VAC. We present the translation, cultural adaptation, field testing, and descriptive pilot evaluation of their Greek versions (HLS₁₉-NAV-GR, HLS₁₉-COM-GR, HLS₁₉-VAC-GR). <b>Methods</b>: Dual forward/back-translation and expert review (11 health professionals/academics) produced the final versions. A purposive, quota-guided field test (N = 71) approximated population distributions by sex, age, education, and geographical region. Test-retest stability (n = 16; ~12 days) was summarized primarily with intraclass correlation ICC (2,1), with Pearson/Spearman correlations reported secondarily. Internal consistency was assessed using ordinal alpha computed from polychoric (polytomous) and tetrachoric (dichotomous) correlations. We report item- and scale-level descriptive statistics for both the original polytomous (four-category, 1-4) responses and a dichotomous difficulty-ease scheme (1-2 vs. 3-4). Given the non-probability sampling in this pilot, the results are descriptive, not statistically representative. <b>Results</b>: Instruments were well accepted, requiring only minor revisions. Scales demonstrated high short-term stability and good internal consistency; inter-scale correlations were moderate, interpreted as associations among related but distinct constructs. Item distributions skewed toward Easy/Very Easy; several HLS₁₉-VAC-GR items showed a clear ceiling, suggesting the need to consider harder items or a larger item pool in future validation. By scale, scores followed the descending order NAV, COM, and VAC. Distributions and ranking patterns broadly mirrored population-level findings from other countries. <b>Conclusions</b>: The adapted HLS₁₉-NAV/COM/VAC-GR instruments are linguistically and culturally appropriate and prepared for large-scale validation, while items NAV9, COM4, and the VAC ceiling are flagged for further assessment.