Gone but not forgotten: knowledge flows, labor mobility, and enduring social relationships

We examine the role of social relationships in facilitating knowledge flows by estimating the flow premium captured by a mobile inventor's previous location. Once an inventor has moved, they are gone-but are they forgotten? We find that knowledge flows to an inventor's prior location are approximately 50% greater than if they had never lived there, suggesting that social relationships, not just physical proximity, are important for determining flow patterns. Furthermore, we find that a large portion of this social effect is mediated by institutional links; however, this is not the result of corporate knowledge management systems but rather of personal relationships formed through co-location within an institutional context that endure over time, space, and organizational boundaries. Moreover, we find the effect is nearly twice as large for knowledge flows across as compared to within fields, suggesting that co-location may substitute for communities of practice in determining flow patterns.