The RPN or Risk Priority Number is a quantitative assessment of risk that is assigned to a process or product function as part of a failure modes & effects analysis.  Individuals or teams assign the RPN based on an established criteria measuring the severity of impact, frequency of occurrence and the likelihood of detection.

  A revision is a number, letter or other identifier that shows the current level of the part drawing.  revision levels show the number of times a part or drawing has been changed.

   A root cause is the beginning or initiating cause of either a condition or a chain that leads to an outcome or effect.  The root cause analysis is often referred to as a weed, if we don’t get to the root and remove the root, the weed will grow back again.  A root cause analysis digs below the surface or the effect in order to discover the initial cause of the effect.  Often times a root cause analysis will travel through levels of causation as it digs towards the root cause. ​

  A raw material is any purchased or supplied item that is in some way transformed via a manufacturing process.  The raw material is generally converted into a component or a finished product.  

​RunTime is the time needed or required to process an item.  It is part of the actual operations time and usually is defined or specified inside of the routing.  The runtime is dependent on the volume or the qty of parts that you are producing.

  The R-Bar chart is another control chart which is used to monitor control of a "range".  The R-Bar control chart tracks the difference between the maximum and minimum values in a subgroup. 

  The RACI matrix is a matrix/tool that is used to track and increase accountability within a project.  RACI stands for Responsible, Accountable, Consult and Informed.  The model is used to organize and clarify projects by listing action items and the responsible individuals.

  Regression analysis is a technique that can help us understand the relationship between two variables.  

  Have you ever had to return a product?  Chances are you have.  Reverse logistics is the supply chain concept that your returns follow.  Rather than following a normal supply chain flow the reverse logistics supply chain focuses on improving the reverse flow.  The focus of the reverse supply chain is to support customer returns, repair of damaged items, remake or remanufacturing of designs that might not meet the customers expectations and recycling materials.  The reverse supply chain can in fact be designed in such a way that it operates at a profit, recovers costs and best of all creates loyal customers. 

  In the comments section below share some ideas that you have that might help returns be a better experience for customers.

Reference: What is reverse supply chain? and Principles of Supply Chain Management.