Firms often attempt to imitate successful practices of other firms.  When implementing new practices, individuals in organizations learn new ways of doing things, develop new skills, and adopt new organizational routines.  In the paper, we view implementation as a learning process and apply learning curve theory to the understanding of implementation dynamics.  We extend classic learning curve to include a required output level for an individual who must choose between an old and a new way to achieve the output.  Doing work the new way builds experience, increasing productivity and thus favoring continued use of the new skill, but this reinforcing process works to favor the new skill only at relatively high levels of productivity.  Otherwise, the same process is a vicious cycle, driving out the new skill.  We use a system dynamics model to demonstrate a mode of behavior in which learning begins and then stalls and another mode in which the new skill becomes the preferred one.  We identify the tipping point between these two modes and characterize the transition problem: Learning by doing is a dynamic process, a transition from use of an old way to a new way that requires accumulating experience beyond a threshold.