Subject: Stocks, Stocks Everywhere

Posted by Tim Joy on 8/13/2010

Message:

In Donella Meadows Thinking in Systems, she speaks of stocks as the memory of a system - an integration of all the inflows and outflows. It's why we look at photos of glaciers from a century ago and compare them to photos from a week ago: same system, way different rates of flow recorded in the stock.

I apply that to the recent Disney trip (July, 2010) and compare it to our earlier one (1996, pre-Fast Pass, pre-shuttle service). Some parts of the experience are better. But I wonder also if the efficiencies are simply lost due to the principle of attractiveness - people go where it's way cool to go: they've fixed the problem of lines at Disney!! Yeah! Let's go! And, well, enough people say that and lines are back up to 60 minute wait times.

In this brief entry, I talk about queues as stocks - customers waiting for service (thank you, John Sterman). Remember, I am not a system dynamicist, but I do occasionally play one in a high school classroom.

Hope you might take a moment to read this: http://itsallonething.wordpress.com/

Just what are the constraints that make some lines longer than others?

Tim Joy
Portland, Oregon

Follow Ups:

Stocks, Stocks Everywhere - Chad Green 8/16/2010