Discovering emerging trends and interdisciplinary mechanisms in urban studies and planning research using topic modelling 1991–2021

This study empirically maps interdisciplinary evolution in urban studies and planning through latent Dirichlet allocation analysis of 44,147 articles from 30 leading journals (1991–2021). We identify 12 research topics organised into three clusters and reveal three distinct interdisciplinary mechanisms: asymmetric knowledge flow where socio-political geography influences planning policy 2.3 times more than reciprocally, unexpected bridge topics with urban-rural development facilitating 54.2% of cross-topic engagement, and methodological integration through spatial analysis tools enabling collaboration across traditionally distinct domains. Temporal analysis reveals rising prominence of environmental sustainability and neighbourhood planning, whilst traditional spatial econometric approaches decline significantly. Co-occurrence network analysis quantifies increasing interconnectedness, with cross-topic authorship rising from 1.6 to 3.2 authors per publication, demonstrating collaborative mechanisms transcending disciplinary boundaries. These findings advance interdisciplinary theory by providing empirical evidence for knowledge synthesis frameworks, revealing how computational methods and collaborative networks serve as practical vehicles for disciplinary integration. The prominence of environmental management and urban-rural development provides data-driven support for contemporary planning paradigms including 15-min cities and Nature-based Solutions. This research contributes novel quantitative methods for mapping knowledge integration mechanisms, offering a replicable framework for understanding interdisciplinary evolution in response to complex societal challenges.