How effort is expressed?
Effort is expressed as a need for time, most often as man-hour, man-day, man-week, man-month or man-year. Thus, effort expresses how many hours, days, months or years it takes for one person to complete a given task or activity.
When and how do we make use of this notion?
It is a metric that can be used to express not only the time-consumption but also the direct cost of the activity or task, as long as we know the price of one hour of a person’s work. For example, in project management, effort is used to estimate the cost of people working on that project. When planning the budget, the planned effort is calculated, then, the actual effort is evaluated at the end of the project.
What is the difference between effort and duration?
Thus, when planning, it is necessary not only to estimate the amount of time the task or the activity takes (i.e. effort), but also the period of time during which it is to be performed - the duration (duration). So, a task that requires 4 man-days (effort) can last for a whole month (duration). Such a task may be performed, for example, one day a week or two hours a day. The remaining capacity of the worker can be used for another task.