A cross-sectional methodological study was conducted between September and November 2022 to evaluate the psychometric properties of the Thai version of the SRAHP Scale among older adults with NCDs residing in community settings across Thailand (
7).
A total of 250 community-dwelling older adults (≥ 60 years) were recruited through multistage cluster sampling from one urban municipality and two rural subdistricts in Ubon Ratchathani Province, with proportional allocation across sites. Participants were eligible if they were ≥ 60 years old, had a clinician-confirmed NCD (hypertension, diabetes, hyperlipidemia, or cardiovascular disease), and had been diagnosed or actively managed within the past six months. Individuals were excluded if they had cognitive impairment (screened using the Abbreviated Mental Test Score < 8/10), severe acute illness, recent hospitalization within the past month, or were unable to communicate in Thai. Sample size requirements for confirmatory factor analysis (CFA) were based on the recommendation of 5 - 10 participants per item (
8). With 28 items in the SRAHP, a minimum of 140–280 participants was required; thus, 250 participants were deemed adequate. To examine temporal stability, a sub-sample of 30 participants was randomly selected to complete the Thai SRAHP again after a two-week interval.
Health-Promoting Behaviors Scale (HPBS), developed by the Thai Health Education Division (
9), includes 19 items across seven domains: nutrition, physical activity, smoking, alcohol use, stress management, rational drug use, and COVID-19 prevention. Items are rated on a 5-point scale (1 = not at all to 5 = completely), with higher scores indicating better health-promoting behaviors. Scores are classified as poor (< 60%), fair (60 - 69%), good (70 - 80%), or very good (> 80%) (
9). The Cronbach’s alpha in this study was 0.75.
The SRAHP Scale, developed by Becker et al. (
2), measures perceived ability to perform health-promoting behaviors in four domains: nutrition, stress management, physical activity, and health responsibility. It comprises 28 items, each rated on a 5-point Likert scale (0 = cannot do at all to 4 = do regularly), yielding total scores from 0 to 112 (low = 0 - 37, moderate = 38 - 74, high = 75 - 112) (
2).
The SRAHP was translated into Thai following Beaton et al. (
10) guidelines, including forward translation by two bilingual health professionals, back-translation by two independent translators, and expert panel review. A five-member expert panel (two public-health nurses, one gerontologist, one behavioral scientist, and one primary-care physician) evaluated the relevance of each item on a 4-point scale. The Item-Level CVI (I-CVI) was calculated as the proportion of experts rating the item as 3 or 4, and the Scale-Level CVI/Average (S-CVI/Ave) was computed as the average of all I-CVI values. This process followed standard CVI calculation procedures. Minor cultural adaptations were made to improve clarity, such as rephrasing ‘exercise’ as ‘regular physical activity’ and clarifying ‘rational drug use’ as ‘appropriate use of prescribed and over-the-counter medications.’ No substantive content changes were required. Cognitive interviews with older adults confirmed that all items were understandable and culturally acceptable. Pilot testing with 30 older adults with NCDs confirmed comprehension and cultural relevance, resulting in the final Thai version for psychometric evaluation.
Data were gathered through face-to-face structured interviews administered by trained research assistants to minimize literacy bias. Each interview lasted approximately 30 - 45 minutes and included both the Thai SRAHP and a demographic questionnaire.
Criterion validity was assessed by examining the correlation between the total Thai SRAHP score and participants’ self-reported health-promoting behaviors. We selected the HPBS as the external criterion because it is the nationally used health-promotion benchmark issued by Thailand’s Health Education Division (
9). Pearson’s correlation coefficients were calculated, with r ≥ 0.50 interpreted as a strong positive relationship. Test–retest reliability was evaluated using the Intraclass Correlation Coefficient (ICC) based on a two-way mixed-effects model for absolute agreement. An ICC ≥ 0.75 was considered indicative of good reliability. As the SRAHP’s four-factor model is theoretically established, exploratory factor analysis was not conducted; CFA was used to verify model fit. Construct validity was assessed through CFA using maximum likelihood estimation in AMOS version 24. Model fit was evaluated using the following indices: χ²/df ≤ 3.0, Comparative Fit Index (CFI) ≥ 0.90, Tucker-Lewis Index (TLI) ≥ 0.90, and Root Mean Square Error of Approximation (RMSEA) ≤ 0.08 (
11). Internal consistency reliability was measured using Cronbach’s alpha coefficients for the total scale and each subscale. Composite reliability (CR) and average variance extracted (AVE) were also calculated to assess convergent validity.