tracking & estimation

I’m confused about how the scheduling of one of my tasks doesn’t match its time estimation. I have the task set for 0.25 days best case and 0.5 worst case. As expected, the 10% Finish is on the same day as the Start day (on a Tuesday). However, the 50% Finish is two days later (Thursday), the 90% Finish is 3 days later (Friday), and the 98% Finish is on the following Monday. How does a 0.5 day worst case turning into several days? (I’m hoping LiquidPlanner doesn’t assume my tasks to be unionized. :D )

Thanks,
Ron

I suspect that this is not the first task in your project. The uncertainty in the end of the preceding tasks will create uncertainty in the start of the tasks that follow. Those uncertainties compound so while the uncertainty in the effort for any given task may be small the uncertainty in the end date could still be quite large because of the uncertainty inherited from the tasks that come before it.

I wonder if I could say uncertainty a few more times? :-)

Yes, Bruce, that task is most CERTAINLY not the last task. It is, in fact, number four. After I posted my first message, I found a entry on how LiquidPlanner determines estimations. During my drive home, I wondered about the stack up in the variance from task to task. If that’s the case, then it makes sense why 0.5 days expands into five days. Of course, your process can only help in determining a realistic completion of a project.

I wish LiquidPlanner had been around ten years ago when I had to try and give completion dates to VPs who didn’t understand why I couldn’t give a specific day. I tried to do a spreadsheet to give me a range of dates but the range usually ended up being between 1 day and 100 years. The VPs were less than pleased when they asked “when” and I answered with confidence, “Some time this century.”

In any case, thank you very much to you and Melinda for helping me.