duration (project management)

Duration of a project's terminal element is the number of calendar periods it takes from the time the execution of element starts to the moment it is completed. Do not confuse duration with work. E.g. it takes three days for a snail-mail letter to arrive from point A to point B, whereas the work put into mailing it may be 0.5 hours. Strictly speaking, the phrase Duration of terminal element X is 5 days is incomplete. It fails to specify the following:the probability with which the completion is expected in the time allotted (since any estimate is only a prediction about the uncertain future, see critical chain)the resources to be used (sometimes using more resources or different resources speeds things up)the assumptions which were madethe author of the estimationthe date the estimate was madethe work schedule of the resourcesetc.
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