3 Tips for Accurately Estimating Project Duration

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ACCURATE_TIMETo the untrained eye, it may seem that when you’re planning a project all you need to do is pull a start date out of the air and that’s when everyone needs to hit the ground running.

You only need to go down that path as a project manager once to realize that doesn’t work. Worse yet, the consequences for not meeting deadline are fierce, and long-lasting. Why is it so hard to determine exactly how long something will take? Let’s discuss it.

Why project duration planning is complicated

  1. People 

Estimating activity duration many times come from the resources that are responsible for the work. This sounds like a great place to start…and it is. There’s no better place to get an idea of what is really involved to complete the work than the person that is responsible.

It’s dangerous to take their word for how long something will take when planning for a project. Why? Because they’re human. People tend to, because of complexity, incorrectly analyse something. They incorrectly breaking it down, and decide it that won’t take any time at all.

This could be for a few reasons

  • They may have glossed over the details and didn’t quite understand what was involved to complete the task.
  • They may not want to look bad in front of their peers and supervisors as to how long something will take and come in with a low-ball estimate.
  • Or, there’s the other end of the spectrum of a ridiculously high estimates based upon overstating the complexity of the project. Neither too high nor too low is acceptable.

It needs to come in “just right” and accurate so you can move forward with confidence when you are planning for a project. But, accuracy can be at times elusive as people are involved.

  1. Processes 

A word of caution, processes can break down and orphan a project somewhere along the way when waiting for approvals, sign-offs, or other checks and balances that have been put in place for the benefit of the project. They are for the purpose of saving time, and this is usually the case. Processes can streamline how long a project takes to move through its phases until it reaches completion. But, it’s hard to estimate when these processes will bog a project down and this will throw you into a “how long will this take?” a tailspin.

  1. Technology 

Most projects today rely upon existing, and more often than not, new technology. This could be in the form of equipment, software, or even hardware. The long-term benefit of utilizing new technology ultimately takes less time to work on a project. However, the short-term reality there are unknown learning curves involved that can throw a wrench into accurately planning duration for a project.

How can you improve accuracy when estimating project duration?

The above provides a better understanding of the challenges that can surface from people, process, and technology when it comes to planning for a project. What are some of the things you can do to improve the accuracy of your estimates and keep your emotional sanity?

  1. Be clear about the final deliverables

As a project manager make it extremely easy for a resource to understand the completion process on a particular activity. In other words, all elements of the deliverable are documented and clear. Sit down with the resource that is responsible for putting the estimate together and work through the details with them. Answer any questions they may have. Eliminate any areas that may come across as vague. Make sure you feel 100% comfortable that they understand the breadth, depth, and nuances of the project expectations. For example, what needs to be delivered – discuss the final estimates together. Spending this extra time will give you the confidence you need for accurate estimates when you are planning for a project. Also, consider using RACI, a responsibility assignment matrix, to help organize project expectations, hence, providing a better time estimation.

  1. Look to the past

Have you done something like this before in the past? Pull out old project plans, lessons learned, and documentation from previous projects that will help you with new estimates. Better yet, added to these documents are the people that did the work. This bit of information will give you a solid basis for activity duration when planning for a project.

  1. Define activity start and stop point clearly

There are certain areas that are black and white when putting together estimates. For example, the marketing department is not going to accidentally stumble into the deliverables that the engineering department is responsible for. Continuing with this example, there needs to be an extremely clear hand off between the engineering function and the QA (quality assurance) function. If that clear hand-off is not in place, the engineering department may feel they’re responsible for performing the QA. QA may not know that the engineering department is performing this function. They then provide an activity duration estimate. As the engineering department has already done this and now it’s duplicate work. Make sure your project plan clearly defines who is responsible for which activity while you are


Activity duration planning for a project is not an easy task. However, over time it that can become easier. You’ll begin to develop a relationship and track record with the resources that put the estimates together. You’ll learn which estimates you can trust, which ones you need to add a little extra time, and which estimates can afford to take a bit off the top. Provide continuous feedback to your teams about how long something actually takes. To conclude, building this type of shared knowledge can prove valuable when the next project gets underway.

Gulit Upadhyay

Gulit Upadhyay

This article was provided by Gulit Upadhyay, a digital marketing engineer at ProductDossier.com, a company dedicated to providing great project management software so that you achieve business excellence.

1 Response

  1. Carlos Vera Tudela Gallesi says:

    Excellent article, thank you very much

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