“Rapid improvement workshop” is another name for kaizen event or kaizen blitz. You may also hear it called rapid improvement project, or “RIP”.
This type of project is generally a week long and includes:
A day of training
A day of process walk / initial planning
Two days of making improvements
A morning of final improvements / wrap-up
A report out
A rapid improvement project is done by a cross-functional team usually led by someone from the leadership team that oversees the process that is being improved. It is normally set with very aggressive goals and is championed by a senior leader in the organization.
See “kaizen event” for a more detailed explanation of this type of project. A downloadable PDF is also available.