Measuring Sustainability: A Validation Study of a Triple Bottom Line (TBL) Scale in Portugal

Abstract

Studies on sustainability using the Triple Bottom Line (TBL) approach are increasing. However, there is no consensus on how to measure the economic, social, and environmental dimensions of sustainability based on TBL theory. Despite numerous proposals, there is a lack of integrated measures covering all three dimensions simultaneously and having a human-centered approach. This gap is particularly pronounced in Portugal, where no existing scale adequately meets the needs of academics and practitioners. To address this challenge, and based on existing measures that encompass the nature of each TBL dimension, we present and validate a 15-item TBL scale, with 5 items per dimension: economic, social, and environmental. To test convergent validity and contribute to the discussion regarding the links between TBL and Corporate Social Responsibility (CSR), we also analyzed the association between each TBL dimension and each CSR dimension. Using a sample of 635 participants, divided into two independent sub-samples, we conducted comprehensive statistical analyses, including exploratory and confirmatory factor analysis, reliability testing, and convergent and discriminant analysis, followed by invariance testing of the TBL scale. The results suggest that the proposed measure fits the Portuguese sample, and all psychometric results are robust. We also establish the links between the three dimensions of TBL—economic, social, and environmental—and the CSR dimensions, as convergent validity is verified between social TBL and employees' CSR practices. We discuss theoretical and practical implications, as well as limitations and suggestions for future research.