This Focused Performance Weblog is a "business management blog" containing links and commentary related primarily to organizational effectiveness with a "Theory of Constraints" perspective. TOC is noted for its applications in Project Management and Multi-Project Management (Critical Chain) and Operations Management (Drum-Buffer-Rope), as well as in Marketing, Strategic Planning and Change Management (TOC Thinking Processes). If you are on an archive page, current postings are found here.
Friday, September 12, 2003
Predicting Uncertain Futures -- James Vornov points out a beautiful example of talking about prediction in an uncertain situation.
When I explain modeling and simulation I often use as an example the atmospheric models used for forcasting. Here's a nice graphical representation of how uncertainty can be represented graphically. You can see the deterministic historical event which is a line through space. At the point representing "now" the line becomes an area. The degree of uncertainty is represented by the increasing area with times further in the future.
Translating to project management, the deterministic line is equivalent to completed work. Looking into the future, we move from points in time to ranges of time within which we can expect completion of a project. The further out we look -- the more work subject to uncertainty that remains -- the wider the range of promises needs to be. As the leading edge of the projected path of the storm starts touching land, that could relate to having the maximum of the range of project promise exceeding the desired due date.
The same way that prediction associated with the map above is important to those living in the potential path of the storm, prediction associated with projects is important to the business and it customers, users, accountants, and lawyers. This is exactly what buffers are all about in a Critical Chain schedule. They represent a range of possibilities for the duration or cost of a project, reflecting best current guesses about an uncertain future with a current, dynamic view of buffer needed for remaining work versus an original buffer and target due date for the entire project. And like the map, provide an easy-to-understand picture of the currently understood cost and/or schedule risks associated with the project.
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