I’ve always had a strong belief that the “shorter" line with people who have just arrived from their weekly shopping trip is always the quickest one. It’s just a concept, but I think the most time-consuming part is when the customer pays. This means the serving time is not directly proportional to the number of items. Regarding studies, it usually takes 30% longer to serve a customer with a shopping cart.

Avg. time needed for a checkout at a supermarket cash register

In addition, there are always annoying variables in the system such as coupons, items without a barcode, etc. With more customers in line, there is a higher probability of anything unexpected.

So, let's see what operations management has for us to solve this ageless headache. Let’s begin with these 2 basic examples:

In case 1, we have a pay desk where on average, 2 customers arrive per minute and the cashier can serve 3 persons per minute. These are the quick-shop, get-some-beer cart guys.

In case 2, - because people see the lots of items – an average of 1 customer arrives per minute and since there are many items, the cashier can serve on average, 2 persons per minute (this is 30% less, as I mentioned before).

After organizing these numbers, we get a table that looks like this:

Avg. time needed for a checkout at a supermarket cash register

The consequences are that you can save an average of 25% of your time by waiting in line; if you go to the line with more items but fewer`` customers. Of course, this quick calculation is far away from research based on empirical data but it’s a good start. Oh, and it was a fun way to spend time because my lovely outdoor activity had been ruined by a shower that had begun while I was shopping… It’s October. I still love it.