This psychometric study aimed to culturally adapt and validate the TIA among nursing and midwifery students engaged in clinical training at teaching hospitals in Kerman Province. Although the original TIA was developed among young adults in Karnataka and Kerala (India), this study involved nursing and midwifery students in Kerman, Iran, owing to the growing prevalence of social media use in this population and the need for a culturally validated measure for clinical education contexts. The instrument’s core constructs are universal, but linguistic and contextual adjustments are necessary to ensure cultural relevance.
The research was conducted in accordance with the ethical principles of the Declaration of Helsinki and approved by the Ethics Committee of Kerman University of Medical Sciences (
IR.KMU.REC.1404.315).
2.2. Study Population and Data Collection
The study population comprised nursing and midwifery students undergoing clinical training in teaching hospitals across Kerman Province in 2025. Cluster sampling was used: First, six nursing and midwifery faculties in the province were randomly selected. From each selected faculty, a list of students currently engaged in clinical placements was obtained, and participants were randomly chosen from these lists.
The sample size was determined on the basis of accepted psychometric research standards and statistical power requirements: 400 students for exploratory factor analysis (EFA), 300 students for confirmatory factor analysis (CFA), 100 students for reliability testing (Cronbach’s alpha and test-retest), and another 100 students for concurrent validity assessment (
11). The samples for EFA (n = 400), CFA (n = 300), and reliability/concurrent validity testing (n = 100 + 100) were independent and nonoverlapping to prevent bias and ensure the robustness of the results.
2.5. Research Instruments
Test for Instagram Addiction (TIA): The TIA consists of 26 items grouped into six subscales: Lack of control (items 1-5), disengagement (items 6 - 11), escapism (items 12 - 16), health and interpersonal troubles (items 17 - 20), excessive use (items 21 - 22), and obsession (items 23 - 26). Each item is rated on a four-point Likert scale (e.g., from “Never” to “Always”), with total scores ranging from 0–78. Each response is scored between 0 and 3, and the sum of all the items represents the overall score. Previous studies have demonstrated good validity and high reliability for this instrument, with Cronbach’s alpha reported at approximately 0.93 in initial samples, indicating excellent internal consistency (
9).
General Phubbing Scale (GPS): Developed by Chotpitayasunondh and colleagues in 2018, the GPS contains 15 items rated on a five-point Likert scale ranging from “Strongly disagree” (1) to “Strongly agree” (5). It comprises four subscales: Nomophobia (items 1 - 4), Interpersonal Conflict (items 5 - 8), Self-Isolation (items 9 - 12), and Problem Acknowledgment (items 13 - 15). The developers reported Cronbach’s alpha values of 0.93 for the total scale and 0.84, 0.87, 0.83, and 0.82 for the subscales. The GPS has been validated for use across various settings and age groups. In Iran, a study by Hasan-Esfahani et al. confirmed its construct validity, convergent validity (correlation coefficient of 0.77 with the Mobile Phone Addiction Scale), and good reliability, supporting its applicability among the general Iranian population. In the present study, the GPS was used to assess the concurrent validity of the TIA, with a Cronbach’s alpha of 0.89 obtained (
12).
In this study, the questionnaire was validated in several stages to ensure the instrument’s validity and reliability.
Although the original TIA had established psychometric properties, content validity [the content validity ratio (CVR) and the content validity Index (CVI)] was reassessed as part of the cultural adaptation process to ensure conceptual, linguistic, and contextual equivalence for the Iranian nursing and midwifery student population. This step aligns with the WHO and Beaton guidelines for cross-cultural adaptation of self-report measures. To assess content validity, 10 experts in psychology, medical education, and linguistics evaluated each item via Lawshe’s three-point Scale (“Essential,” “Useful but not essential,” “Not essential”) for CVR and a four-point scale (1 = not relevant to 4 = highly relevant) for CVI across simplicity, clarity, and relevance dimensions (
13).
Concurrent validity was evaluated by calculating the correlation between the total score of the TIA and the GPS Questionnaires. The GPS was selected for concurrent validity because both phubbing and Instagram addiction share core features of compulsive smartphone use, social withdrawal, and impaired interpersonal engagement. The GPS reflects behavioral and cognitive components similar to those underlying Instagram addiction, thus providing a theoretically and empirically grounded external criterion.
Construct validity was examined through EFA and CFA. In the EFA, the Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy and Bartlett’s test of sphericity were first calculated. The latent factors were then extracted via the principal axis factor (PAF) method with varimax rotation. Items loading on each of the six factors were identified, and all factor loadings exceeded 0.50, indicating a strong association between the items and their respective factors (
14). PAF was chosen because it extracts common variance and is appropriate for identifying underlying constructs rather than maximizing total variance, as in principal component analysis (PCA). Rotation was initially performed via varimax rotation for clarity and interpretability of factor loadings, but the results were also verified via oblimin rotation given the theoretical likelihood of correlated psychological dimensions. The two methods produced comparable factor structures, confirming the robustness of the factor solution.
The CFA was subsequently conducted to assess the fit of the model derived from the EFA. Model fit indices included the chi-square test, root mean square error of approximation (RMSEA < 0.08), comparative fit Index (CFI > 0.95), Tucker-Lewis Index (TLI > 0.95), standardized root mean square residual (SRMR < 0.05), normed fit Index (NFI > 0.95), incremental fit Index (IFI > 0.95), relative fit Index (RFI > 0.95), and root mean square residual (RMR < 0.05) (
15). The CFA was conducted to confirm the six-factor structure identified by the EFA and to validate the theoretical model of the TIA. As a standard psychometric procedure, CFA verifies construct validity from both data-driven and theoretical perspectives. Given that the Persian version was culturally adapted for Iranian nursing and midwifery students, this analysis was essential to confirm the stability, model fit, and replicability of the structure from the original Indian version, ensuring that the adapted instrument retained its theoretical coherence and multidimensional nature.
Reliability was evaluated via Cronbach’s alpha, split-half reliability, test–retest, and Guttman’s lambda coefficients (λ1 - λ6) to provide a more comprehensive assessment of internal consistency. Test–retest reliability was calculated over a two-week interval between administrations of the TIA.
Data analysis: Prior to analysis, the collected data were checked for completeness, as were the presence of outliers or missing values. Missing data were checked and handled through listwise deletion, as the number of missing values was minimal (<5%). No extreme outliers were identified. Statistical analyses were conducted via IBM SPSS Statistics version 24 (IBM Corp., Armonk, NY, USA) and LISREL version 8.8 (Scientific Software International, Inc., Skokie, IL, USA). In the descriptive phase, measures of central tendency and dispersion, including the mean, standard deviation, frequency, and percentage, were used to describe demographic characteristics and main variables. In the inferential phase, facial validity was assessed both qualitatively and quantitatively; content validity was determined via the CVR and CVI; concurrent validity was examined via Pearson’s correlation coefficient; and construct validity was evaluated via EFA (KMO and Bartlett’s test) and CFA (model fit indices). Reliability was assessed through Cronbach’s alpha, split-half, and test–retest methods, with the significance level set at P < 0.05.