Project estimates are the next step after you WBS is ready. In this module, you will learn how to proceed when estimating work efforts needed for every deliverable/activity on your WBS. By the end of the module, you will also know the various factors that must be taken into consideration when estimating. Remember, your estimates are not sufficiently accurate, your whole project schedule is going to collapse!
You have now your WBS in hand. You know, which activities will have to be completed so that all project goals and objectives are met as required by the project sponsor and other stakeholders. The WBS with appropriate project estimates are the foundation of your future project schedule (and financials). Therefore it is important to complete the project estimation tasks with special care.
Project estimates are expressed mostly in the unit of man-days or man-hours. The number of man-hours on a task represent the amount of time needed for completion of this task.
What to take into consideration:
For each individual it may take a different amount of time to complete a certain task. There are many factors that may influence this duration eg. the level of education achieved in the specific domain, the extend of previous experience, capacity of an individual to quickly learn and adapt etc.
When assigning human resources to individual WBS activities, you need to take many factors into consideration too: eg.:
- How difficult and complex is this task to complete?
- Is there a requirement for certification associated with this task?
- How fast does it have to be done?
- Are there many risks involved?
- Who needs to engage in delivery? Who should cooperate?
- How high is my budget?
- Which human resources are there available in that moment?
Do not forget, that all your estimates should be based on the data submitted or approved by the task owners if possible. In other cases, it´s adviced to get an expert opinion on your tasks or discuss them with fellow project managers experienced in the particular domain of your project.
Take-away No. 1: Never adjust your estimates to the expected outcome! If the final budget exceeds the original assumptions, re-check your estimates, re-consider the assignement of specialists high on the learning-curve and re-check project priorities from the perspective of scope!
Take-away No. 2: Be cautious with estimates of your subcontrators. There are good reasons why they may under- or over-estimate their parts of the work. Get a clear understanding of their scope of work. Re-check!