What Is Activity Duration?

Activity duration describes a sub-component of time that occurs between the onset of a project and its completion. Depending on the setting, this duration may be more specifically defined as the time it takes to launch and complete a task that is part of the activity, or the total duration involved in starting and ending an activity or project. Typically, activity duration is presented in some sort of time elements, ranging from seconds or minutes all the way through to days or months.

The actual start time for calculating activity duration will often depend on how project managers choose to identify the actual beginning of the project. In some cases, the start time will be the date and time that the project first went into development. At other times, the identified start time will be the date that the project or activity is approved. A third option is to identify the start date as the actual date and time that work on the activities necessary to complete the approved project are commenced.

There is also some variation on when to set the end time in an activity duration. For example, this component of the activity duration may be identified as the specific date and time that all necessary tasks associated with the activity are completed. An alternative that may apply to projects such as launching a new product line may set the end date as the date and time that the products are actually made available to buyers.

In order to accurately calculate activity duration, it is imperative to identify what is meant by the start date and end date, and apply those definitions consistently throughout the activity or project. Doing so makes it easier to determine how much time is left until the anticipated duration is reached, which in turn aids in gauging if the project is ahead or behind schedule. In terms of using this process to evaluate how quickly employees are handling specific recurring tasks, such as in a manufacturing environment, identifying the actual activity duration and comparing that duration to production and efficiency standards will often help in assessing the productivity of an individual employee. The activity duration may also help when it comes to evaluating the processes associated with the activity itself, possibly leading to changes in those processes that shorten the duration and make the activity more efficient.