The impact of two forms of environmental agency supply on public space use among older adults in nursing homes: a cluster-randomised field experiment

Environmental control in nursing-home public spaces is usually treated as a matter of physical conditions, although residents often depend on staff to change those conditions. We conceptualise environmental agency supply as the opportunity created by institutional rules and environmental arrangements for residents to act on, or choose among, available conditions. We tested two forms of this supply in a mixed factorial, cluster-randomised field experiment involving 544 residents in 36 nursing homes across three climate zones in China. Direct control access was randomised between facilities, and preset microclimate choice was assigned within facilities as a crossover. Direct control access increased target-space occupancy by 6.36% points despite prompt staff responses in the comparison condition. Preset microclimate choice increased occupancy by 3.88% points relative to near-uniform conditions. Occupancy of other public spaces also increased, and no interaction between the two protocols was detected. These findings show that the organisation of environmental control can itself shape spatial use: authority to act and selectable environmental variation should be treated as design properties of institutional public space alongside physical conditions.