Behavioural Trajectories and Spatial Responses: A Study on Lag Sequential Analysis and Design Framework for Elderly Caregivers in Chinese Dual-Earner Households

The present study examines the behavioural trajectories and spatial utilisation of elderly caregivers within intergenerational families, set against the backdrop of China’s accelerating ageing population and the widespread prevalence of dual-income households. Existing studies predominantly rely on static data, which makes it difficult to capture the dynamic relationship between behaviour and space. The present study employs lagged sequence analysis in combination with non-participatory observation and video recording techniques to conduct a 14-day behavioural tracking and sequence analysis of two typical dual-income families in Beijing (totaling 2137 behavioural events), thereby establishing a research framework of “behavioural observation, sequence analysis, and design translation.” The identification of three typical behavioural sequence patterns was achieved through the implementation of behavioural coding, spatio-temporal trajectory modelling, and sequence correlation testing. The identified sequence patterns are as follows: a simple “cooking–eating” sequence, a complex “child-centred” sequence, and a cyclical “housework–rest–communication” sequence. These patterns exposed fundamental contradictions with prevailing spatial functions. The study proposes synergistic spatial and furniture design strategies to support elderly caregivers’ behavioural flow, alleviate caregiving burdens, and foster intergenerational integration. This research not only validates the methodological value of lag sequence analysis in behaviour-driven design but also provides theoretical and empirical foundations for sustainable residential environments that promote intergenerational cohesion and reduce caregiving stress.