This study aims to use a time-to-event framework (Cox survival analysis) to provide duration-based evidence on how sustainability report disclosure and sustainability assurance relate to environmental, social and governance (ESG) performance persistence (defined as the time until an ESG rating declines), a method rarely applied in ESG research.
Using 2016–2024 data for publicly listed companies in Taiwan, this study uses a Cox time-dependent survival model to estimate the time to an ESG rating decline. The analysis distinguishes disclosure types (voluntary, mandatory, non-disclosure) and assurance types (accounting-firm assurance, non-accounting-firm assurance), further separating Big4 from non-Big4 accounting firms and identifying whether the same accounting firm provides both the statutory financial statement audit and the sustainability assurance (dual assurance).
Voluntary disclosure is associated with longer ESG performance persistence relative to non-disclosure. Mandatory disclosure is associated with longer persistence only for firms subject to higher capital-based thresholds. Non-accounting-firm assurance is associated with longer persistence, whereas accounting-firm assurance shows no significant association, irrespective of Big4 status or dual assurance.
This study applies a survival-analytic perspective, which is underutilized in ESG research, to capture the temporal dynamics of ESG performance persistence and to appropriately treat right-censored outcomes. By focusing on time to rating decline rather than point-in-time averages, this study provides duration-based evidence on corporate sustainability practices.
