Résumé (EN)

In this paper, we consider a model of on-the-job learning where workers learn informally by watching and imitating colleagues. We estimate the rate of knowledge diffusion inside the firm using three matched worker-firm data sets from Benin, Morocco and Senegal. We rely on non-linear least squares to estimate the structural parameters of the informal learning model and account for unobserved firm heterogeneity using firm factors derived from a principal component analysis. We find that the rate of knowledge diffusion is around 7 percent in Morocco and Senegal and much higher in Benin, but part of the learning-by- watching returns stems from firm heterogeneity. Informal training significantly affects the shape of returns to tenure in African countries. Finally, we estimate an extended model with both learning-by-watching and learning-by-doing and find significant benefits from imitating colleagues in Morocco.