And now—for something completely different—PERT (with apologies to Monty Python!)
One of the bigger headaches with projects is in estimating
how long each task is going to take. By definition, a project is a unique
undertaking, and thus it is likely that few or any of them have been done
before. We are in a lucky position if we have some areas that have been
done before, as we can examine their history and make much more accurate
estimates using the previous experience. We might want to update that
experience based on the conditions pertaining now. Is the same resource going to
be assigned? What is the experience and skill of a different worker? What conditions will pertain this time round (eg., weather, time of year,
business, co-workers, etc)? Difficult isnít it?
There are any
number of techniques available to help estimating, like rule of thumb,
parametric (see: http://www.ispa-cost.org/PEIWeb/newbook.htm), analogous, analytical and
bottoms-up estimating. These mostly require some specialist knowledge and
experience, so what has Project got? PERT.
Allow me to explain...
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