Successful projects start with accurate schedules. As project managers, you are expected to know how long it will take to complete a project. Regardless of whether you’ve carried out a similar project before, it will likely be overwhelming to assign time at the milestone level. However, if you break each milestone down into individual activities or tasks, it will be much easier to assign a realistic time to the activity.
When creating a schedule, one of the first things a project manager must realize is that projects are not carried out in isolation. Bad things can happen to good projects. That said, you should anticipate problems and obstacles and factor in buffer time for the instances where the project could be derailed. Project tasks are more commonly underestimated than overestimated, so adding a reasonable amount of time to a specific activity or milestone is acceptable.
There are no set rules or procedures for estimating activity durations. Estimating is not a science, but rather an educated guess. You might be asked for a ball-park timeline, a high level budget plan timeline, or a firm project schedule. Regardless of the use or formality of the estimate, the nine tips listed below will help you increase your estimating ability today.
1. Document Assumptions and Factors
Document all assumptions and factors that went into creating the estimate. This will allow anyone who views the estimate to be aware of how the number was reached and provides a baseline for the estimate.
2. Add Time for Requirements Gathering
If the project is large, complex, or completely new, ensure you estimate ample time up front for requirements gathering and the estimating process. If there are no experts whom you can ask for help, you will be stuck figuring it out on your own, so allow enough time to work through these initial stages.
3. Set-up Contingency Plans
Set-up contingency plans for critical path items, unanticipated events, and risk. The more you know about potential risks that can affect critical path items, the better. This will help you manage your timelines and estimates upfront.
4. Involve Other People/Resources
Involve as many people as you can in estimating activity durations. Between you, experts, and your resource team, everyone should be happy with and agree upon the time it takes to complete the activities. The more people involved in the estimating process, the more accurate your estimates will be.
5. Avoid Scope Creep
Create an activity list from the work breakdown structure (WBS) and follow it. Once the WBS is complete, and the project is disaggregated into manageable chunks, you can create an activity list that describes each of the tasks that need to be completed during the project. The activity list should include all of the required activities, assumptions, restrictions for each activity, along with the assigned resource. The WBS activity list encompasses the scope of your project and will ensure all tasks are included on the project schedule.
6. Ensure You are Comfortable with the Estimate Provided by Resources
Be aware that people often underestimate activity durations. Underestimation isn’t done intentionally; people simply tend to think it will take less time to complete their tasks than it actually does.
7. Track Actuals for Every Project
Track actual completion times for all projects and tasks. This will allow you to see how accurate your estimates are, and will prove to be an invaluable resource if a similar project arises again.
8. Be Aware of ‘That Time of the Year’
Be cognizant of the time of year during which your project will be carried out. From illnesses during back-to-school, to Christmas season, to summer vacations, there are certain times every year that will almost guarantee resources will be out of the office and unavailable. Make sure you pay attention to this and of your resource pool.
9. Add Required Training Time to Schedule
If training is a prerequisite for gaining appropriate project skills, be sure to include the time for training in your task estimate.
In conclusion, better estimates produce more accurate schedules. Schedules that will instill confidence in the project manager, the project team and that will often define whether a project will succeed or fail. Most importantly, learn from your past mistakes by estimating your way to a more reliable schedule!