A number of theoretical models of technology adoption have been proposed that emphasize technological switching, loss of expertise and subsequent technology-specific learning. These models imply that measured productivity may initially fall and then later rise after the adoption of a new technology. This paper investigates whether or not this implication is a feature of plant-level data from the Colombian manufacturing sector. We regress measures of productivity growth at the plant level on a plant-specific measure of technology adoption and its lagged values. We find that...