Advancing multi-timeframe developmental research through combining long-term cohort and ecological momentary assessment studies: The Decades-to-minutes (D2M) study

Within developmental science, there is a gap between our understanding of long-term ‘developmental’ processes, investigated via traditional longitudinal cohort designs, and our understanding of short-term ‘momentary’ processes, investigated via lab-based studies or, increasingly, via ecological momentary assessment (EMA) methods. To bridge this gap, multi-timeframe studies that link momentary processes to long-term developmental trajectories are needed. One promising approach is to embed studies of momentary processes within long-term cohort studies. This is the design of the decades-to-minutes (D2M) study, which combines a burst of EMA (n=255 young adult participants) with a 13-year longitudinal cohort study of development from childhood through to adulthood. Here we describe the rationale for, and design of D2M and provide an illustrative dynamic structural equation modelling analysis from the data. We also provide suggestions for future developments in the design and implementation of multi-timeframe studies. We conclude that embedding EMA within existing longitudinal studies is an efficient, feasible and scientifically valuable approach to studying development across multiple timescales and suggest that future studies of this type on a larger scale would be valuable for the field.