This study examines the time–frequency dependence structure and causality of Vietnamese financial development (FI), trade openness (OP), education (ED), and digitalization (DI) on Vietnam’s economic growth (GDP) across quantiles over the period 2000–2021. We employ wavelet-based decomposition series to establish a multiscale quantile-on-quantile regression (QQR) and Granger causality in quantiles test frameworks to uncover the complex interactions involving FI, OP, ED, DI, and GDP. The results are as follows: First, QQR findings indicate that digitalization and education significantly impact economic growth across different quantiles. By contrast, there are both negative and positive relationships between FI, OP, and GDP in this economy at various economic scenarios. Second, as for the Granger causality test, the findings are heterogeneous. Put differently, a bidirectional relationship is found between FI, ED, DI, OP, and GDP in this country at different timescales. This Granger causality is stronger in longer time horizons. Additionally, wavelet coherence estimates suggest that the multiscale nexus between the examined variables is time-varying and scale-varying, where we find low coherence in the short run and higher coherence in longer time horizons. These findings can inform cooperative policies on digitalization, education, trade openness, financial development, and economic growth in Vietnam.
Ngà et al. (Sun,) studied this question.