What is the difference between effort and duration

Project Effort Effort is the number of labor units required to complete a Task. Project Duration Duration is the total number of work periods required to complete a task. Elapsed Time Elapsed time is the total calendar time needed to complete a task. Example of Project Duration, Effort, and Elapsed Time Let us consider a small task that involves painting one large wall. It means that painter s will work 8 hours per Day. The painting task has a Duration Estimate of 4 work days with only 1 painter working.

There is no scarcity of painters. There are enough painters available to do the task. All painters have equal productivity. The amount and quality of the work is same for each painter. The task will start on Friday. Saturday and Sunday are holidays. Duration If 1 painter works, the duration of the task would be 4 work days or 32 work hours.

If 2 Painters work, the duration of the task would be 2 work days or 16 work hours. If 4 painters work, the duration of the task would be 1 work days or 8 work hours. Elapsed Time If 1 painter works, the task will start on Friday and finish on Wednesday. The elapsed time would be 6 days. If 2 Painters work, the task will start on Friday and finish on Monday.

The elapsed time would be 4 days. If 4 painters work, the task will start and finish on Friday. Help Center Learn the platform. Often it can be hard to understand the profound difference between effort and duration. So, let us take a moment to examine this distinction and why it is important. What does effort mean? What does duration mean? How the terms relate Once you have an effort estimate, you have to estimate the duration.

Example If you have 2 teleporters that have to be set up, and only one teleportation expert, you are not going to be able to do those three tasks in parallel. Installation and set up of 2 teleporters is estimated to take 80 hours. How schedule relates These two terms relate strongly to schedule, which is the project timeline. Summary When you are working towards a deadline, understanding and tracking the difference between duration and effort will allow you to schedule the time to spend on other tasks and still make your deadline.

A few classical quotes on this topic from Frederick Brooks book The Mythical Man-Month: Essays on Software Engineering Men and months are interchangeable commodities only when a task can be partitioned among many workers with no communication among them.

This is true of reaping wheat or picking cotton; it is not even approximately true of systems programming. The added burden of communication is made up of two parts: training and intercommunication. Each worker must be trained in the technology, the goals of the effort, the overall strategy, and the plan of work. This training cannot be partitioned, so this part of the work varies linearly with the number of workers. Since software construction is inherently a systems effort - an exercise in complex interrelationships - communication effort is great, and it quickly dominates the decrease in individual task time brought about by partitioning.

The duration is usually expressed as working days or working weeks and depends on the availability and capacity of the resources. However, if the friend could work only 2 hours a day, the duration would extend to 6 days because the resources would only work for a total of 5 hours a day.

The total effort is always 30 hours, no matter if there are one, two or more people working on the project. It is not possible to reduce the effort to 15 hours if two people work on the project, but it is possible to reduce the overall completion time. The estimates represent one of the most critical and complex areas for a project manager. It is never certain that these are correct and there is always the doubt that they may be mistaken for excess or defect , despite all the good will in formulating them.

The estimation techniques , such as the analogy or bottom-up estimations, can provide more or less reliable estimates, but all have the same problem: they depend on the capabilities of those who formulate them. In other words, there is the tendency to increase, even exceedingly, the estimate of duration due to excessive prudence. Clearly, if everyone in the company, including the project manager, uses this technique, the final estimate would be totally exaggerated and misunderstood.

This chiefly depends on the measure of time members of the project spend on the project. A simple example to explain this concept follows. You work for 6 hours a day for 9 days. Your effort would then be the amount of time you take in a day multiplied by the number of days you work, which would be 54 hours.

The effort you put in is 54 hours. Duration is defined as the entire time taken to complete an activity, based on the resources allocated to the project. It stretches from when the task first began to the day it ended and does not include time off like holidays or other non-working days. It is also referred to as calendar time.

Take the same example given for effort. You begin to paint your living room. You work for 6 hours a day for 3 days. The time duration of your work painting the living room is 3 days.