If someone asks you “How long will it take for you to drive home from the grocery store?” you could probably give a very accurate estimate, especially if you made that drive many times before. If they ask you “How long will it take you to fix the facet?”, (and you don’t even know what’s wrong yet) could you give them a very accurate estimate, or would you rather make some assumptions and give a range of estimates? “Uncertainty” should drive us to provide a range of estimates, especially if we are expected to commit to a completion time.
Does this above scenario apply to efforts you estimate for work? If so, how do you come up with your commitments?
Go one step further – are you responsible for the execution of complex projects (with many tasks and people involved, some of whom you may not know)? If so, how do get to a credible project plan, and then, how do you communicate and defend it? My answer would be “By applying 3-point estimates for uncertain (i.e., risky) tasks and using a Schedule Risk Analysis (SRA) tool to analytically evaluate the confidence levels for various estimates.”
The first response I typically hear is “That sounds reasonable, but it seems complicated and hard to do!”. I might even agree with the second part of that response if it wasn’t for a new software tool called Chrono™. So, say that I’m right about this new tool – wouldn’t it be worth a try?
Here is what you do. Create an Integrated Master Schedule (i.e., a schedule that links tasks together so that when tasks are completed the whole schedule automatically adjusts accordingly to show how you or your team is doing) and give all tasks you best single-point time estimates. If you do this with Microsoft Project, you can use Chrono™. That is where the typical planning process ends. But let’s not end there. Work with your team to come up with two more estimates (Best-Case and Worst-Case), but only for the “risky tasks”. Then enter them using the Chrono™ Wizard and run the Simulation. Boom! You did it! Your Schedule Risk Analysis output chart is automatically generated within a few seconds and displayed in your Web Browser. This is not that complicated if you have the right tool to help you!
You might be wondering what the “risky tasks” typically are. The usual culprits are listed below:
Here on some hints for how to get Best-Case and Worst-Case task duration estimates: