O'PEEP'S FIRST PASS YIELD EXPLANATION
You are determined to produce 1000 nice cookies to support the local Christmas market. They must look really nice. Unfortunately every 20th cookie is just a pile of crumbs. You must eat it immediately. (Scrap it!). From what’s left every 10th cookie can be saved with chocolate decorations. (We consider this rework). Your First Pass Yield measures how many cookies are fine straight away. At the same time it indicates how much extra effort you are facing because your dough is not very good.
The First Pass Yield (FPY) is a metric that describes the percentage of good parts produced without any rework with respect to total production. FPY also helps measure the success of your continuous improvement strategy.
Take a look at this diagram to see how to calculate FPY when multiple processes are involved.