How should I ramp up my mileage after injury?

I have a great question from a runner who was injured and is now recovering. 
 
She is getting better, she is back to running, she is advancing her mileage, she is increasing her strength, and her stability. And she asked me during a call whether or not she should follow some specific formula to get back to running. 

She asked me about the "10% rule." 

How should I ramp up my mileage after I have been injured but I am returning to running? Should it be by percentage? Should it be by miles? What is it? 

Well, good question and that is what we're talking about today on the Doc On The Run Podcast.