How to create and use predictive project scheduling

I was a bit naïve when I accepted the challenge to manage my first software project. I didn’t quite understand the “wink-wink, nod-nod” I got from the software veterans when I began asking for their input to the project task detail and schedule. Now many years and many projects later, I understand their skepticism. They had too often been victims of schedules that were not worth the paper or time used to develop them. They had seen schedule chicken played by professionals and had worked countless hours of overtime trying to meet unrealistic, unattainable deadlines.

However, I continue to believe whole-heartedly in the value of predictive schedules. To me, a predictive schedule is one that accurately reflects what has happened in the past and is a good predictor of the future.  It gives a believable prediction of the project end date and an accurate level of effort estimate to completion.

What are the necessary pre-conditions for a useful predictive schedule?

Let me tackle the most challenging requirement first—corporate or organizational culture. If your company has a “shoot the messenger” ethic, then predictive scheduling is doomed! Like a military plan, the initial project schedule rarely survives contact with the enemy. Staff changes, requirements creep, and vendors miss shipment deadlines.  Your project schedule must be detailed enough to identify potential problems and dynamic enough that you can reforecast to accommodate the real world. AND, senior managers need to be willing to hear the impact of changes on the project schedule.

For predictive scheduling to be useful, there must be trust on all sides of the equation:

  • As project manager, you do the best you can to create an accurate and meaningful schedule of tasks with an estimated level of effort (LOE).
  • Developers and team members work hard to meet schedule requirements and accurately record their time to each task as well as update estimate to complete (ETC).
  • Management trusts that everyone involved is doing their best and reporting accurately.  They provide support when needed.

What content is required for a useful predictive schedule?

Developing a predictive schedule is a top down and a bottom up process. You must start with the top level vision and goals for the project to set expectations and scope.  Then each deliverable is broken down into tasks that require no more than one or two week’s time to complete (that task may include the effort of several people or it may require less than the full-time effort of one developer). The point is that you need to be able to assess the project’s status weekly.

Now we come to the one of the most powerful features of predictive scheduling—task dependencies. Your schedule must show these dependencies. What must be completed before “Task X” can begin (predecessors) and what tasks depend on the successful completion of Task X (successors). Getting the task dependencies correct is 50% of the requirement for creating a useful predictive schedule.

The other 50% is estimating the effort really required to complete the task successfully. As project manager, you will want the input of others on the project to define tasks, dependencies, and effort. Then, you have to make a judgment on their input. First, you need to make sure that there is enough detail so that the schedule can document the project status and second, you will likely need to adjust the estimated level of effort (LOE).

Why do I believe that the initial effort submitted by developers will need to be adjusted? Developers and other team members often make errors of omission and commission in defining LOE for a task. (Dan Mitchell offers some insight into what may be left out of developer’s estimates on his Software Developer’s Guidebook blog). Some may be too optimistic—assuming all of their time will be dedicated to writing code when in reality the schedule needs to include time spent in meetings, unit testing, and working with temperamental hardware and software. Or, they may assume that the level of productivity is the same for all developers or IT staff, when the truth is that some developers are significantly more productive than others (usually based on experience or skill).

Finally, either through misplaced self preservation instinct or lack of knowledge, developers may over-estimate LOE believing that if the estimate is cut during its migration through senior management reviews, they will still be able to get the work done because they padded their initial estimate.  So you, the PM, must assess the estimates and try to get them to be as accurate as possible!  No one said this was easy.

What benefits does a project manager receive from a real predictive schedule?

  • Ammunition to define and defend resources needed to be successful
  • Knowledge of project status with sufficient time to avert disasters
  • The ability to answer status and planning questions from senior management
  • A final project that predicts cost and schedule throughout the project’s life

One last thought: predictive scheduling tells a PM what he or she needs to know, not what they may want to hear.

Please comment and share your thoughts on predictive schedules.


(If you want more on why you need predictive schedule check out the earlier post at

6 Responses to “How to create and use predictive project scheduling”

  1. Glen B. Alleman Says:

    The notion of schedule modeling through development of duration estimates is well understood in many software domains outside of traditional IT. Monte Carlo simulations of very large software projects are the basis of weekly discussions on many programs we work on. For some reason – laziness I’d say – corporate IT has yet to come to understand how to do this in a useful manner.
    I really think it is beacuse they don’t really want to know. In the absence of this knowledge they can continue to belive the fiction of the static schedule.

  2. Asking for Help « Fear No Project – A Project Management Blog Says:

    […] Situations that lead to eventual project problems or outright failure come in two flavors—project specific and systemic. As part of effective project management, before beginning work you created a project schedule and a risk management plan, which included indicators of potential problems. Missing milestones or falling behind on interdependent tasks are yellow flags to project managers that may signal the need to ask for help. (see: Spotting a failing project and How to create and use predictive project scheduling) […]

  3. Dean Hiller Says:

    and so that is why we created’s predictive project management tool ;). Just google “Predictive Project Management”. It adjusts those initial estimates for you ;).

  4. “A Fool with a Tool is Still a Fool” | Fear No Project Blog - Focusing on the Management Side of Projects Says:

    […] Human beings believe in the power of tools to make work easier and solve problems. For centuries, until recent work of biologists and zoologists proved us incorrect, we believed that the use of tools distinguished humankind from lower animals. In previous posts, I have talked about tools I believe are essential to effective project management (Collaboration Tools  and How to create and use predictive project scheduling). […]

  5. Top Ten Questions You Should Ask about Every Project You’re Managing | Fear No Project Blog - Focusing on the Management Side of Projects Says:

    […] becomes more useful?  I don’t believe in wall paintings that are schedules.  A schedule must be predictive of what is planned and […]

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

The Lazy Project Manager's Blog

The Home of Productive Laziness Thoughts

Thoughts, experience, tips and tricks on issues affecting managers and project management

A Girl's Guide to Project Management

Project Management musings for one and all

LeadingAnswers: Leadership and Agile Project Management Blog

Thoughts, experience, tips and tricks on issues affecting managers and project management

Project Management Hut

Thoughts, experience, tips and tricks on issues affecting managers and project management

Herding Cats

Thoughts, experience, tips and tricks on issues affecting managers and project management


Pushing the Edges Out ...


Just another site

%d bloggers like this: