Suppose I am an inventory manager. (I’m not, but that is beside the point)
I get a delivery of 10 boxes. Each box is labeled “1 of 10”, “2 of 10”…“9 of 10”, “10 of 10”.
Now, not only do I need to verify that I have indeed received TEN boxes, but also that I have numbers 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 specifically and not, say, a box marked “32 of 47” included in that 10.
Is there a name for this double check method of counting?
The idea that you have to count twice is a fallacy. If you are keeping track of the numbers as you receive the boxes, you will only have counted once. Here’s how: When you see the first box, it will say (for example) “Box 3 of 10.” Now you know how many boxes to expect and which one you’ve gotten. Take a scrap of paper (if necessary, you can also just keep up with it in your head) and write the numbers 1 through 10 on it (note that in writing down ten numbers, you haven’t counted anything). Cross off number 3 to indicate that box 3 has arrived.
As each successive box comes in, cross off it’s number. Any box number which falls outside the range (“Box 32”), has the wrong denominator (“of 47” from the OP’s example), or repeats a numerator (“Oops, that makes two 3s!”) indicates a problem. Ten numbers crossed off later and no problems, and you’re done. You haven’t counted anything twice.
OK… I KNOW that I just meant that there were TWO different things to keep track of. The reason I am asking is so that when I write an operating procedure it would be nice if there was a name I could use to describe the process.
Not that I’ve ever run into. This is more of a real-world problem than a combinatorical one, so you’d probably be better off asking people with their PhD’s in inventory management.
It does have an official name. However, it’s more precisely an inventory question versus an accounting question. The term you want is “specific identification.” Most inventory methods are either this one, FIFO (first-in, first-out), or LIFO (last-in, first-out). The importance as it relates to accounting is that your inventory cost on the books could either be “specific identification=ridiculously accurate,” “FIFO=most recently purchased, so a higher cost on the books,” or “LIFO=earliest purchases, so a lower cost on the books.” It’s ok to use any of these methods; it just depends on your goals.
