Al-Qadisiyah University AL-Qadisiyah Journal For Administrative and Economic sciences 1816-9171 28 1 2026 04 01 Bayesian composite quantile regression for longitudinal count data 106 115 191430 10.33916/qjae.2026.01106115 EN Mohammed H. AL-Sharoot University of AL-Qadisiya Sabaa Muhammed University of AL-Qadisiya Journal Article This paper develops a composite quantile regression framework for the analysis of longitudinal count data. Unlike classical regression approaches that assume a continuous response, the proposed method explicitly accounts for the discrete nature of count outcomes while preserving their inherent smooth structure. The model is constructed using a flexible representation based on a growing mixture of asymmetric distributions, which allows the conditional distribution of the response variable to be captured across multiple quantiles. To facilitate Bayesian inference, a structured Gibbs sampling algorithm is derived for parameter estimation. The performance of the proposed approach is carefully evaluated through extensive simulation studies, demonstrating its robustness and efficiency under various data-generating scenarios. Furthermore, the methodology is applied to a real dataset from the field of neurology, illustrating its practical relevance and interpretability. Comparative analysis with existing models highlights the advantages of the proposed composite quantile regression approach for longitudinal count data. https://qjae.qu.edu.iq/article_191430_6b48303c0ebaa7191a4df1e07d1a5147.pdf