The performance of a project manager with a long history of managing projects is a good predictor of future projects. If their performance has been consistent, they will have earned the long rope. This means that their performance need not be managed as frequently or as closely as lesser experienced project managers. If their performance has been erratic, they will have earned a short rope. Their performance will have to be more closely and frequently monitored.
These are the newbies and until their performance proves otherwise, they will be managed with a short rope. They will be monitored with more specific metrics and smaller tolerances. Corrective actions including learning opportunities will be put in place and monitored for compliance. They will have to earn the right to be managed with a longer rope.