Difference between Effort & Duration

Many times our clients ask us “How much time do you need to complete this task?”

Typically the development teams respond by saying “It will take 12 hours to complete it” or “It will be completed in 12 hours”.

The above two sentences have two completely different meanings.

“It will take 12 hours to complete it” refers to an effort of 12 hours required to complete the work.

“It will be completed in 12 hours” refers to the duration within which the task will be completed.

Having said that, lets understand the difference between the terms “Effort” and “Duration”.

Effort refers to the number of person days or person hours required to complete a task. e.g. 12 hours of effort: This means if one person worked on this task nonstop, they can complete the task in 12 hours.

Duration refers to the time period required to complete the task. e.g. 12 hours duration: This means the task will be completed in 12 hours’ time. i.e. This statement does not say how many people will be working on it. It could be 3 people working for 8 hours of effort each and getting it ready within 12 hours duration. It could also be that one person will be working on it for 3 hours of effort, but will have time to complete it only in 12 hours’ time.

In order to get out of this confusion, we have set certain guidelines to be used by our teams whenever interacting with clients on topics of effort and duration.

While giving a proposal/estimate, we always give two numbers:

• Estimated Effort
• Estimated Duration

Also when replying to any client queries on when a task will be ready, we give them two data points: one about effort and the other about duration.

Tip: Estimates should always be performed based on the effort. Plans should always be performed based on the duration.