Project managers spend a lot of time attempting to develop the perfect project schedule with bottom-up estimates. Despite all the upfront planning with well-defined single point estimates, projects still experience schedule slippage, late tasks, and unwelcome surprises, as uncertainty occurs throughout project execution.
A typical approach to scheduling uncertainty is to add time buffers at the task or phase level that expand the project duration and provide enough “cushion” for you to handle unknown project delays. This approach works as long as the amount of uncertainty doesn’t exceed the project buffers.
When PMs communicate dates, they often use absolutes, which don’t allow for fluctuation based on a best case or a worst case estimate. Although PMs try to forecast the future, they haven’t invented a project tool to predict the future. Consequently, it makes sense that we should start planning and communicating our schedules by incorporating uncertainty.
LiquidPlanner: A unique way to handle project scheduling
I have been looking for an alternative to my current approach for scheduling uncertainty, and I was pleased to learn about LiquidPlanner. This Web-based project scheduling and collaboration tool will likely change the way PMs think about project scheduling.
I recently interviewed Charles Seybold, CEO of LiquidPlanner, to discuss managing uncertainty in a project schedule. According to Mr. Seybold, “Unmanaged uncertainty is the silent killer of projects. The good news is that it’s not hard to manage uncertainty once you can visualize it. The easiest way is to build that insight from the bottom up with ranged estimates and a realistic scheduling method, which is exactly what LiquidPlanner does. To put it simply, you can’t manage what you can’t see.”
How it works
Instead of selecting a specific date to complete a task, LiquidPlanner uses a ranged estimate that allows you to specify a best case and a worst case duration estimate. Then, LiquidPlanner’s scheduling engine applies statistics to determine the probability of completing a task by a given date (Figure A).
Sample project schedule with ranged estimates. (Click the image to enlarge.)
Instead of specifying a single point duration estimate, you can enter a best case and a worst case estimate, and the scheduling engine will calculate the duration ranges with task completion confidence levels. In Figure B, a given task’s duration will have a best case early start, a best case finish, an expected finish, and a worst case finish based on a probability calculation. Based on the calculations, the software forecasts a recommended promise date with a 98% confidence. As the project progresses, the duration date range will adjust and, if promise dates are passed, the system will automatically alert the project stakeholders.
Task Duration Bar with probability ranges. (Click the image to enlarge.)
I built a sample schedule using LiquidPlanner’s free 30 day trial, and I found it very easy to build tasks in a project schedule. Also, LiquidPlanner’s implied dependencies were useful for developing a project schedule; instead of adding explicit dependencies between tasks, LiquidPlanner assumed the subsequent task was dependent upon the predecessor. In a waterfall project schedule, this feature is useful, as resources and task start and finish dates automatically adjust based on the order of the tasks. In situations where the order doesn’t always imply a dependency, you can explicitly define predecessors with a few mouse clicks and create a chain of dependent tasks.
Another useful feature in LiquidPlanner is the dynamic resource management; as resources were assigned to tasks, the dates automatically adjusted and displayed the probabilistic completion dates for the entire project. You don’t need to resource level the plan since Liquid Planner automatically performed the calculations. The project end date also didn’t unrealistically expand, as the date range provided a best case and a worst case completion date for the project.
Tool is consistent with expert advice
In Neal Whitten’s book No-Nonsense Advice For Successful Projects, he writes about applying rolling planning and only committing to a milestone date a few weeks in advance. He advises against committing to a launch date months in advance when priorities can change. As the team accomplishes the milestone, then they commit to the next milestone date. LiquidPlanner supports this approach by providing the PM a promise date and a range of probably completion dates instead of rigid dates that were established months ago without incorporating uncertainty.
Benefits of ranged estimates
For the traditional PM, the LiquidPlanner approach is a variant to the PMBOK standard of activity definition, sequencing, resource allocation, and duration estimation. However, PMs will quickly see how useful ranged estimates can be in planning a project and communicating a project end date with a confidence range instead of an explicit date. The ranged estimating approach also relieves some pressure from the project team to be 100% correct in their estimating and encourages the team to plan for change. LiquidPlanner helps teams visualize uncertainty, and PMs can do a better job of planning for it once they see the potential impacts.
I encourage you to visit the LiquidPlanner site, sign up for a free 30 day trial, and watch the company’s training videos. In a future article, I’ll explore some of LiquidPlanner’s collaboration features that also help effective project delivery.
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