Why estimate in ranges?

The single-point estimates (i.e., “10 days”) that most software programs use are usually padded guesses instead of realistic estimates.

Ranged estimates capture the amount of uncertainty associated with each task. If the range is quite large, the amount of uncertainty is high. If the range is small, the task duration is relatively certain.

LiquidPlanner sees each range as a bell curve and uses it to calculate an expected completion date.

The set of ranged estimates in your project provides the data LiquidPlanner uses to statistically determine all of the possible schedule outcomes. This data appears on schedule bars in the Schedule tab.

Estimating in realistic ranges is one of the single best and easiest things you can do to improve your project outcomes.

Ranged estimation will change your team’s perspective on work and scheduling and move conversations from uncomfortable negotiations to open and honest dialogue about requirements and ways to work together constructively to get rid of uncertainty.

Estimating in ranges is a transformative shift forward in project management thinking and is an excellent method for managing risk.

When you make ranged estimates, you should try to be at least 80% confident that the actual outcome will fall in the range. 

The easy way to think of this is as reasonable best-case and worst-case estimates.

LiquidPlanner translates these effort ranges into schedule ranges and does statistically correct rollups on the projects.

Remaining Effort

Note that effort is very different from “number of calendar days until this task will be done .”  Task estimates in LiquidPlanner represent the amount of work (specifically the amount of remaining work) there is for a task. If a task is estimated at 5-10 days that means one should expect to put in 5-10 full days of work before it is done. That’s different than saying I will be done in 5-10 days. For instance, if my availability is set to half days, then LiquidPlanner will schedule that same task to complete in 10-20 calendar days because that’s how long it takes to get 5-10 days of work done if one works half time

Entering Estimates

Estimates are entered via the work tab in the task edit pane. 

To enter or update an estimate simply enter your best-case and worst-case estimates for how many days or hours it will take you to complete the task. The two values should represent a range of effort in which you’re about 80% confident that the actual effort to complete the task will be between.

The default unit will be shown on the detailed edit pane. You can enter both estimates and progress in any unit by adding the unit letter after the number like this:

• 2d (for 2 days)
• 2h (for 2 hours)
• 15m (for 15 minutes)

The number you enter will be displayed back in the workspace default unit. (Only your workspace owner can change the workspace default unit.)