7 Techniques for Creating Project Estimates
How do you create project and task estimates? Do you use old data to help plan for current or future projects? Do you elicit feedback from co-workers? Do you use formulas or guestimates to help you create your schedules?
Here are 7 techniques to help a BA create estimates:
- Use historical data. Simple reference what was used in the past and apply it to what you are doing. If you spent 2 hours in a kick-off meeting last year, the same time may be reasonable for the next kick-off meeting.
- Ask someone how long it will take. Asking co-workers and other stakeholders how long something will take to complete is a great way to determine estimates. Based on the feedback you can apply a number of techniques to determine time estimates.
- Parkinson’s Law. This is the law that time of a task expands to fill the time given. Meaning that if you think something will take 6.5 hours to complete and you work an 8-hour day, there is a good chance that it will take you the full day to complete the task.
- The real work day. In an 8-hour day do you really spend all 8 hours working? Chances are you don’t. Pick a reasonable amount of time that you will actually spend working. Take the full day and subtract the time you spend checking your email, playing on the internet, chatting with co-workers, answering phone calls, and taking breaks. In an 8-hour day you might work 6.5 hours of actual productive time. Remember this in your calculations and estimates.
- Scotty S(Double it). This is based on the character from Star Trek where Scotty will say that a task takes twice as long as it really should. This way when he completes the task that he looks like a miracle worker. I have actually seen formulas out there that explain this. After a developer gives you a quote, you add your time, the PM adds their time, and the testing team adds their time that the overall time to complete that item is usually double what the original estimate is.
- Management Tax. After all the estimates have been calculated I like to add what I can management tax or an extra 20% on the overall time. This tax will allow for the project team to have their meetings, status reporting time, phone calls, OMG moments, or whatever time they “need” to complete the project or task.
- Pert weighted average. This is a calculation that takes estimated feedback from stakeholders and allows you to create a time based on the best case scenario, worst case scenario, and most likely scenario.
Best time + (4 X Most likely) + worst case divided by 6 will give you your average estimate.
For example: If the fasted time you can complete a task is 3 hours, but most likely it will take you 5 hours to complete and if something goes wrong it will take 10 hours your formula will look like this:
3 + (4×5) + 10 / 6 = 5.5 hours to complete the task.
These are just a few ways to help you create your project estimates. Practice them and see what works best for you, your team, and your projects.