When we are approaching the checkout in the supermarket how do\u00a0we decide which queue to join?\u00a0 Is it the shortest? Is it the one with the fewest number of full trollies? Is it the one that is staffed by the most competent looking operative? Or is it the new-fangled computerised one that technophobes like me avoid like the plague? If our goal is to get out of the shop as quickly as possible then this is an important yet tricky decision. Once\u00a0we have committed to a specific queue then\u00a0we are bound by the social norms to stick it out.<\/p>\n
Technically speaking the queue to join is not the shortest one, or the one with the where there are the smallest number of individual items that need to be scanned, or the one with the fastest operative – it is the queue with the smallest load<\/em> – the cumulative product of the number of items and cycle time of the operative. Hence\u00a0our quick mental calculation of length of queue * average size of trollies * speed of operative.\u00a0 Even then it can go wrong if someone throws a spanner in – such as picking up the only item on the shelf with a missing barcode – triggering the need to call a “supervisor”!<\/p>\n Are\u00a0we completely powerless in this process? Not at all –\u00a0we each can ensure all our purchases have barcodes and\u00a0we can also influence the cycle time of the operative. Observe what they are doing – picking up each item in turn, finding the bar code, and turning the item so that the bar code can be easily scanned by the computer.\u00a0 To shorten the cycle time all\u00a0we have to do is make the work for the operative as easy as possible by placing each item on the moving belt in the correct orientation and spaced so that the speed of the belt delivers the items at the same rate that the operative can scan.\u00a0 This sounds counter-intuitive but it works!\u00a0 It is just\u00a0like the variable speed limits on some motorways – by slowing down you get there faster because the flow is smoother – there is less “turbulence” created.<\/p>\n There are two potential\u00a0flaws in this counter-intuitive strategy though – the people in the queue behind you may start “tutting” because they believe you are playing childish games and slowing the process down (which is incorrect but we are social animals and we\u00a0copy other people’s behaviour and react to “social deviants”).\u00a0 The other flaw is that, if\u00a0I am\u00a0shopping alone\u00a0I cannot both stream my purchases for optimal scanning and also pack my\u00a0scanned purchases into\u00a0my reusable shopping bag!\u00a0 So,\u00a0I may only be able to use this strategy\u00a0when accompanied by a trained assistant\u00a0and have access to\u00a0my fast getaway car!\u00a0 Of course\u00a0I might get even more radical – and offer to stream the shopping for the person in front of me while they pack their scanned items. But that would mean that we work together to achieve a common goal – to reduce the (life)time we\u00a0all spend waiting in the shopping queue. This way\u00a0we do not need an assistant or a getaway car and shopping might even become more sociable.\u00a0 Everyone wins. What everyone? How is that possible?<\/p>\n","protected":false},"excerpt":{"rendered":" When we are approaching the checkout in the supermarket how do\u00a0we decide which queue to join?\u00a0 Is it the shortest? Is it the one with the fewest number of full trollies? Is it the one that is staffed by the most competent looking operative? Or is it the new-fangled computerised one that technophobes like me … <\/p>\n