Development of a Sustainable Logistics Service Level Agreement (SLSLA) Model: a Partial Least Squares Structural Equation Modeling and Measurable Index Approach

الملخص

The increasingly complex development of the logistics sector requires service level agreements that are oriented not only toward operational efficiency but also toward sustainability. This study develops and empirically validates a Sustainable Logistics Service Level Agreement (SLSLA) model comprising seven dimensions—operational efficiency, reliability, responsiveness, digital transparency, environmental performance, customer satisfaction, and resilience—operationalized into 28 reflective indicators. A quantitative survey was distributed to logistics practitioners and academics selected through purposive sampling; of 50 questionnaires distributed, 40 were valid for analysis (80% response rate) after 3 were omitted owing to absent values or anomalies. The implementation of Partial Least Squares Structural Equation Modeling (PLS-SEM) that utilize SmartPLS aimed to deliver data analysis. The convergent validity of the measurement model was satisfactory (outer loadings 0.867–0.944; AVE 0.798–0.824), high construct reliability (Cronbach's Alpha also Composite Reliability with value above 0.90), sufficient discriminant validity (Fornell-Larcker criterion and HTMT go under 0.90), as well as no collinearity problems (VIF 2.235–3.012). Bootstrapping with 5,000 resamples confirmed that all seven dimensions contributed positively and significantly to the SLSLA construct (t-statistics 10.093–16.150; p < 0.01), with relatively balanced path coefficients (0.169–0.177), so that hypotheses H1–H7 were fully supported. The resulting SLSLA Index, weighted by path coefficients, reached 70.93 on a 0–100 scale (high category), led by digital transparency and operational efficiency, while reliability and customer satisfaction contributed relatively less. The validated SLSLA model and index offer logistics service providers a measurable reference for designing and evaluating more sustainable service level agreements.