Most operations maintain at least some numbers on the most critical aspects of the business. For order picking operations, you might track number of orders picked per day, hours per pick, cost-per-pick, on-time rates — and error rates. The question is this: how accurate are those numbers? For instance, if your system reports 50 order picking errors a week, does that represent half your errors? All of them? Most of them? It’s can be difficult to understand.