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from prior literature. The dependent variable, sustainable purchasing behavior (Perchase
Green Products - PGP), was measured with 5 items adapted from Chan and Lau (2001)
and Ramayah, Lee, and Mohamad (2010). Five independent variables (Price, Green
Knowledge, Perceived Quality, Social Influence, Green Marketing) and three moderating
variables (Influencer Endorsement, FOMO, Financial Literacy) were each measured with 5
items.
All items were originally developed or sourced in English and translated into
Vietnamese using a forward-backward translation procedure: items were first translated
into Vietnamese by a bilingual research team member, then independently back-
translated into English by a second bilingual translator, with discrepancies resolved
through discussion (Brislin, 1970). A pretest was conducted with 15 university students
and two faculty reviewers to assess item clarity and cultural appropriateness; minor
wording adjustments were made before final deployment.
3.4. Analytical procedures
Data analysis followed a systematic four-stage process using SPSS: (1) Descriptive
statistics for sample profiling; (2) Reliability testing via Cronbach's Alpha (threshold α ≥
0.70); (3) Exploratory Factor Analysis (EFA) with KMO ≥ 0.50, Bartlett's test p < 0.05,
Eigenvalue ≥ 1.0, factor loadings ≥ 0.45, and total variance extracted ≥ 50%; (4)
Hierarchical moderated multiple regression with multicollinearity diagnostics (VIF < 10),
residual normality testing (Kolmogorov-Smirnov), homoscedasticity assessment, and
autocorrelation testing (Durbin-Watson). (5) To assess common method bias (CMB),
Harman's single-factor test was performed by entering all 45 items into an unrotated
principal component analysis (Podsakoff, MacKenzie, Lee, & Podsakoff, 2003). The first
unrotated factor accounted for 34.42% of the total variance, which is well below the
conventional 50% threshold, indicating that common method variance is unlikely to
constitute a serious threat to the validity of the findings.
4. Results
4.1. Reliability analysis
Table 2 shows that all measurement scales demonstrated satisfactory internal
consistency reliability. Cronbach's Alpha coefficients ranged from 0.804 (Social Influence)
to 0.909 (FOMO), with all values exceeding the 0.70 threshold. All corrected item-total
correlations exceeded 0.30, confirming item-level reliability.
Table 2. Reliability statistics
Construct Items Cronbach's α
Sustainable Purchase (PGP) 5 0.828
Price Perception (P) 5 0.855
Green Knowledge (GK) 5 0.902
Perceived Quality (PQ) 5 0.877
Social Influence (SI) 5 0.804
Green Marketing (GM) 5 0.893
Influencer (INFLU) 5 0.887
FOMO 5 0.909
Financial Literacy (FL) 5 0.897
4.2. Exploratory factor analysis
EFA was conducted separately for independent variables, moderating variables, and
the dependent variable. For the five independent variables: KMO = 0.873, Bartlett's test χ²
= 2302.517 (p < 0.001), five factors extracted with eigenvalue ≥ 1.0, cumulative variance

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