I am trying to find a proper indicator for a small number of items. We have a production of large items, where the number of items procued daily is very small and varying. Some days, we produce 2 items and others, we would produce 30. When looking at the First Pass Yield, we sometimes get 0% FPY when we have 2 items repaired for 2 items produced, but would get 50% FPY when we get 15 repairs for 30 items produced. Even if the second case shows better FPY, we feel the quality is not that good, as the first one does not have as much chance of showing true quality. What kind of indicator can we use that would show the "quality" of production, depending on the production size?