How to calculate a performance ratio when your goal is zero?

Question

When it comes to performance ratio the standard answer is quite simple. Let's say for example we have a car manufacturer who aims to manufacture $1000$ cars and he just made $900$ so have here $\frac{900}{1000}=90\%$ he has made $90\%$ of his objective.

But in another scenario we have flaws ratio our purpose is $0$ and we have made $10$ flaws so how can we calculate a ratio of the flaws since $\frac{10}{0}$ is not the right answer?

Answer 1

One possibility would be to compute the ratio of flaws to total. So for instance if you had $10$ flaws among $50$ items, your ratio would be $20\%$, with the goal being $0$.

Answer 2

If your goal is to make flaws and your target was 0, then 10/0 is the right answer.

However, your goal was probably not to make flaws: your goal is probably more like make unflawed widgets, and that is a very different problem.

Answer 3

Flaws ratio is always connected to another measurement. Like flaws/lines of code, flaws/hour flaws/car.

In that way you can measure your flaws made and set your goal:

Bake 100 breads with 0 flaws.