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Better Estimates Next Time

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It's hard for me to predict the future. Although our team meets project deliveries, we normally range from -5 percent to +15 percent of the scheduled delivery date with one exception. We struggled on one project and finished past the promised delivery date by 50 percent of the project schedule.

We documented lessons learned much like what Dmitri Ivanenko has described in a previous post.

But I was not satisfied, so I surveyed my colleagues on how they thought we could better estimates next--and every--time.

Here is what they said:

•    Anticipate volatility and plan frequent feedback opportunities with customer. If every project you manage starts with a solid set of requirements that never changes, count yourself lucky. Most of the time, that's not the case. Be in the mindset that projects go through changes and have frequent feedback sessions with your customers to help minimize last-minute surprises.

•    Utilize both top-down and bottom-up approaches. Visions, objectives or problem statements provide the boundary of the project scope. Agree on top-level requirements and then work with the experts on coming up with quality estimates for the detailed tasks. Clarify any assumptions/questions during this time and use A Guide to the Project Management Body of Knowledge (PMBOK® Guide) processes and/or any parametric modeling tools to create the initial schedule.

•    Plan the high-risk item(s) early. How many times have you seen a schedule task showing 90 percent complete only to have it continued at 90 percent for a long, long time? Make sure the risky development work is scheduled up front. This practice gives you the greatest flexibility on mitigating risks you may not have planned for.

•    Assess your team's experience with the project effort. Understand how experienced the team is with the kind of problem you are asked to solve. And staff the project with the right people for the jobs even during planning stage. You may not need all of the positions filled, but you will need to have experienced experts to provide quality estimates.


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It was interesting to know that peers have an interest in improving the accuracy of project estimates.
Working at the IT department of a shipping company, we would base on several approaches 1) historical projects could possibly offers some insights on the estimates for the new project 2) bottom-up estimating where we identify the activities, the resources needed to complete the task and the duration required.

Hope this helps.

Maureen Gan

Hi Victor,

My third bullet point is very applicable in your firm's desire to use Critical Chain to scheduling.

Avoid the following: 1) ambiguous/conflicting management directions therefore causing teams to waste schedule buffer time due to bad multitasking, 2) work the high risk schedule items up front so that teams don't procrastinate until the last possible moment to start on those tasks which end up burning the buffer time faster than you can manage, 3) remember the phrase "good enough" and don't let teams gold plate thus wasting what buffer schedule you have left to mitigate other tasks on the chain.

Best Wishes!


We are exploring the Crical Chain approach to scheduling.

Do you or anyone else have any practical advice from implementing it from a pros and cons standpoint?

We are an architectrual and engineering firm doing over 200 projects a year.

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