Reading the LP schedule bars (a.k.a. Uncertainty Gantt bars)

Only LiquidPlanner has a scheduling system that allows you to capture, view, and manage uncertainty in your project schedule. This flexibility is the result of estimating tasks in ranges (e.g., 5 - 15 days) instead of single, fixed estimates (e.g. 10 days). Think of this as creating a best-case and a worst-case scenario for completing a task.  Once you enter your ranged estimates, LiquidPlanner does the hard math to create a statistically correct schedule you can trust.

LiquidPlanner calculates probable start and finish dates for each of your tasks and displays this data to you in the schedule bars: 

Earliest Start

The earliest start is the soonest you are 10% likely to start this particular task.   The assumption is that you can’t start a task until the preceding task completes, so the the actual start date of the task is uncertain. To de-clutter your display we chose to show this as the earliest LiquidPlanner thinks you might be starting this task.   

Earliest Finish (10% likely)

This is the earliest you could conceivably finish this task or container (project, sub-folder or package).  For a task, this corresponds to the best-case (low) estimate.  For a container, this corresponds to the date on which you are 10% likely to finish all of the tasks, for all people, in that container.  

Expected Finish (50% likely) 

You are 50% likely to finish this task or container (project, sub-folder or package) on or before this date.   This is the date you should be shooting for.  For a task, this corresponds to the mid-point of your ranged estimate.  For a container, this corresponds to the date on which you are 50% likely to finish all of the tasks, for all people, in that container.  

Latest Finish (90% likely)

This is the latest you are likely to finish this task or container (project, sub-folder or package).   For a task, this corresponds to the worst-case (high) estimate.  For a container, this corresponds to the date on which you are 90% likely to finish all of the tasks, for all people, in that container.  

Taken together, the Earliest Finish (10%) and Latest Finish (90%) give you an 80% confidence interval.  That’s a fancy-pants way of saying that you’re 80% likely to fall somewhere between those two dates.

98% Finish (98% likely)

This is the latest you could conceivably finish this task or container (project, sub-folder or package).  It is the date on which you are (unsurprisingly enough) 98% likely to have finished.   

How to use expected dates and deadline dates 

The Liquid Planner visual system is designed to help you focus your attention on two things: 

• Work diligently towards the E, re-estimating as you go. Treat it as your target, and if you are doing it right, ½ the time you will be under, ½ the time you will be over.

• Treat the end of the bar as the safe promise/deadline date. This is the 98% confidence date.

Use deadline dates to your advantage. You can set a deadline date on any item in the plan and if the E gets too close to the deadline date the system will start alerting you with red “on fire” flags.  Set a deadline date on a container and all of its children will inherit that deadline date.

Seeing interruptions in the schedule bar

When a task is subject to a pending interruption, such as an event or higher priority delayed task,  we show that interruption period in the schedule bar.  In the sample below, the Client Design Review task will get started, but before it's finished, it will be interrupted when the Hawaii Vacation event starts.  It will resume after the event is finished: