To continue the unintentional theme of cars as metaphors for lean…
I equate the creation of defective products and services to making a wrong turn and getting lost while driving.
First of all, you’re ending up where you’re not supposed to be despite investing time and effort. With defects, you’re providing something the customer doesn’t want, and in a car you’ve spent time and fuel going somewhere you don’t want to be.
However, what we sometimes fail to realize is that we now have to go back and fix the problem and that adds additional investment of time/money/effort. If you’ve driven away from the specified path, you wasted resources getting there and now must spend more resources getting back to where you were before. You’re making a loop just to get back to where your trip went awry. You will most likely end up following the path you just took, just in reverse.
With defective product, you also have to consider resource usage going forward. Do you spend time/money on reworking the product (and make a loop just to get back to where you started)? Or do you simply throw away the sunk investment of time/money and get nothing back for it?
(Of course, “throwing it away” really isn’t an option in a car. You have to get to your destination. You don’t just abandon the plan and never make it there or home.)
You are using your resources to the best of your abilities if you follow the directions accurately and if you verify the process you’re using will create products/services the customer wants.
Using a map or a GPS unit will help guide you on your journey in the car and help prevent mistakes, just like a process recipe or standardized process document will help create the right product. However, those tools do you no good if you choose not to follow them. The GPS doesn’t mandate you follow the route provided (although you might hear “Recalculating route” over and over). A standardized work document doesn’t verify that the operator is following the prescribed process.
You, as the operator of the car and of the process, must have the proper self-discipline to know that the information provided by the tools (GPS, map, standardized work document) is accurate and will guide you to do the right thing. Doing the right thing all the time will help in your goal of utilizing resources as best as you know how.