Time needed to complete a task, activity, or project
Effort refers to the number of labor units required to complete a task, activity or project, and are often called ‘man-hours’. Effort is usually expressed as either
- time units (days, hours, minutes)
- a monetary value,
- or material needs.
In project management, estimating the effort required to complete a task or activity in a project serves as a foundation to determine the duration of said tasks, activities and therefore the project. If e.g. a project must be completed within 3 weeks and each work week is defined as having 5 work days with 8 hours each, but the effort required for completing all the tasks exceeds these limitations, the consequences are either
- to require people work overtime,
- to put more people to the tasks (which can mean higher costs),
- extending the deadline,
- or reprioritizing the tasks and thereby changing the scope of the project.
Each change automatically affects what is known as the Project Triangle: scope, time, and cost.
- The difference between the time spent on e.g. a task (effort) and the time frame within the task must be completed (duration) is best illustrated by this example: Writing a project proposal takes 6 hours. To complete this and hand it in to your superior you have 5 work days (Monday-Friday). In order to deliver the project proposal until your deadline on Friday 5 p.m., you need to start working on your project proposal on Friday morning at 10 a.m. at the latest, if you also want to pop out for lunch. The duration of the task is 40 hours (5 work days with 8 hours each) until your deadline, but you only need to spend 6 of those on this one task.