I had a hallway conversation with my colleague about the best way to manage a project schedule. My colleague admitted to developing a pretty Gantt chart at the beginning of the project because executives like pictures. He also admitted that he wasn’t sure how accurate or up-to-date the schedule was with reality. When I asked how does he know whether the project is on track, he replied, “I manage with my gut.”

I pushed him a little more on this point because I can’t do my job properly without a valid project schedule, and believe:

“If you’re gonna manage it, you need to measure it.”

I’ve known others who have succeeded by managing with their gut but I still prefer the data that tells me the project schedule really is on track. His response to my “measure what you manage” belief was “I’d do more tracking and realistic scheduling if I didn’t have 10 other fires to put out.” My response to this is: If you build a realistic and predictive project schedule, you won’t have so many fires to attend to, since a predictive schedule provides greater reliability. Fewer surprises.

Let’s take a closer look.

Predictive vs Pick-a-Day Scheduling

Predictive scheduling is the scheduling technique that relies on predecessors and resource constraints to forecast meaningful task start and end dates. If you’ve ever built a schedule using a predecessor column and linked tasks, then you’ve taken your first step in developing a predictive schedule.

In predictive scheduling, the project start and finish dates are dynamic. They adjust based on actual project progress and are compared against project commitment dates or a project baseline. Predictive schedules require a little more time to create since you’re analyzing the dependencies and resource commitments. In a predictive schedule, you actually want the dates to adjust based on the resource availability and task dependencies. The benefit is a more realistic project schedule because it models the “real world” by including resource constraints, resource availability and dependent tasks

Conversely, pick-a-date scheduling (i.e. fixed date scheduling without logical dependencies) does not take any of the previous criteria into consideration. Pick-a-date scheduling is exactly what it sounds like—selecting a singular. The problem here is that if a task is dependent upon another task or if a preceding task slips, there’s no clear way to identify an impact on the project schedule.

Where does pick-a-date scheduling fit?

Pick-a-date scheduling is often driven by clients and project stakeholders who have likely already picked a date before the project has even started. This is usually driven by a business need or some previously communicated delivery date. The challenge for the project manager is to balance these expectations with the realistic effort to deliver the project on-time, within budget and within scope. For portfolio planning purposes, I’ll pick a date at the three-month or six-month level. These dates are used to provide a rough order of magnitude for top-down budget planning. If I have more time and more details, I’ll provide more realistic details with a predictive schedule.

However—there’s an important difference between the two:

• Pick-a-date scheduling is used to communicate a goal or a desired delivery date.
• Predictive scheduling should be used to validate this top-level decided date and confirm if the desired date is viable.

If you’re executing a project schedule without reflecting reality, you’re at best guessing and hoping you’re right.

You can probably guess which method I prefer.

How a Predictive Schedule Helps Manage Teams

A predictive schedule helps manage project teams in the following ways:

1. All team members know the impact to their work.
2. You have greater confidence knowing if you’re going to meet the project launch date.
3. The task start and finish dates adjust based on team performance.
4. The project manager can accurately forecast completion dates without having to guess if a team member is available or if a task can start on time.

Let’s look a little closer at these predictive schedule benefits:

All team members know the impact to their work

Everyone wants to know that their work matters. In a predictive schedule, if a single task is late and impacts another task, all the team members can see the shift in their own dates. With the pick-a-date method, your team members don’t necessarily know if your task will impact their work or not because there are no dependencies. A predictive schedule incorporates real world constraints—it shows resource availability, task dependencies and resource allocation to ensure that the schedule reflects real world execution.

Greater confidence

A predictive schedule helps the team communicate with greater confidence to meet project commitments. As a project manager, you can examine the project’s critical path and quickly assess if the end date adjusts. If a task slips, the team not only knows the impact but the person who is accountable can help realign the deliver date.

Automatic date adjustment

If you ever planned a complex schedule in spreadsheet, then you know how difficult it is to keep the dates updated as well as forecast future dates. In smaller projects, a spreadsheet check list is fine but in large projects, you need a predictive schedule to forecast date changes. The main benefit is the time saved administering the schedule which provides more time to communicate with the team. Some folks new to predictive scheduling may be surprised when the date shifts, but that’s the entire point of building a dynamic and predictive schedule. The dates should adjust automatically based on task performance.

It’s your job to make sure that the finish dates align to the original commitment date.

Forecast completion dates without guessing

If you’re not using a predictive schedule, you’re simply guessing at dates without considering to resource constraints and task dependencies. With a pick-a-date schedule, you’ll find yourself pushing team members to complete late and current tasks all at the same time. This is unrealistic and increases stress rather than increase productivity.

With predictive scheduling, your team will do great work and forge lasting relationships because of the strength of working toward realistic dates and assignments. As the PM, you’ll lead a team to great heights by determining realistic dates based on logic instead of guessing.

Ready to give LiquidPlanner and predictive scheduling a try? Start your free trial today.