Schedule Density

I have mentioned the work being done by the CIOB (UK) to develop a practice standard for scheduling in a few posts. This valuable work is now at the public comment stage and has a number of really innovative ideas.

The concept of schedule density contained in the CIOB ‘guide’ is not dissimilar to rolling wave planning but has far more practical advice.

The concept is based on the idea that it is practically impossible to fully detail a schedule for a complex project at ‘day 1’ – too many factors are unknown or still to be developed. The CIOB advice is to plan the overall project at ‘low density’, expand the work for the next 9 months to ‘medium density’ and plan the next 3 months at ‘high density’.

Schedule Density Over Time

Low density activities may be several moths in duration. Medium density activities are no longer than 2 months and focused on one type of work in one specific location. High density activities are fully resourced, with a planned duration no longer than the schedule update period and with specific workers allocated.

Activites are expanded to increase density

As the ‘density’ of the schedule is increased, the plan takes into account the current status of the work, current production rates and what is required to achieve the overall objective of the project.

This approach has a range of advantages over more traditional ways of scheduling not the least of which is engaging the people who will be responsible for doing the work in the next 2 to 3 months in the detailed planning of ‘their work’.

More later.

13 responses to “Schedule Density

  1. Pat,

    Great concept. We use PERTChart Expert to make a picture of the density of work for large programs.
    The Gantt view is misleading at times, because it does not show the density of deliverables, since there are summary tasks, level of effort tasks and other “glue” needed to hold the actual work together.

    With PERTChart Expert (, and with you ANSI-E plotter (always needed for any program controls shop), you can see right away the labor profiles and effort density for the program.

    As well, with the chart hanging on the wall and time phased in the IMP/IMS paradigm, everyone sees how the maturity of the deliverables moves from left to right as well as the dependencies between the Work Packages that produce the products that create the increasing maturity.

    • Thanks for the comment Glen

      Not mentioned in the post (and far from obvious in the sketches) is another tenet of the CIOB Guide. They require all schedules all of the time to be fully linked with every activity having at least one successor connected to its end and one predecessor connected to its start.

      When published early next year I believe this Guide will be an invaluable reference for schedulers world-wide but having contributed to it I’m biased….


  2. Hi Pat, can you publish the actual link to the standard, can’t seem to find it in the main page.



    • Hi Shim,

      The Guide is only at the draft stage and was released for public review to CIOB members and an invited range of academic and industry leaders. The review period is about over and the final editing has started.

      Watch this space in the New Year for details of the release of the Guide.


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  4. Pat,
    In the Defense Contract Management Agency 14 Point assessment, similar “tests” of credibility are done.

    There are tools for running the 14 point assessment that we use every week on the baselined Integrated Master Schedule.

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  6. I appreciate this concept of “Schedule Density” very much, and the white paper explains it very well, thank you very much!
    Is there a similar established term like “Density” which explains the idea that an activity can be broken down to different levels of detail, depending on the level of control needed?
    An example: a team needs to create 5 complex documents. This can be scheduled as either one activity (1 activity in total), there can be one activity per document (5 activities in total), there can be separate activities for writing but one for reviewing and revising the entire package (6 activities in total), or separate activities for writing, reviewing and revising each document (15 activities in total).
    Is there such a concise term for this concept like “Schedule Density”, or would you just call this “Level of Detail”? It is similar to Density, but different in the sense that I make a concious decision not to break down a task further, even if I could.
    Background of my question: I see a tendency with many of my colleagues to break down the schedules to a level of detail which is unhandy, because if a certain “checklist”-minded thinking and I would like to explain that they make a conscious decision on the appropriate level of detail.

  7. Pat, Thanks for this. I’ve been looking for a good framework that brings progressive elaboration to construction schedules. One question I have is how does this take into account change orders for future work that are still at the summary level?

    In a conventional schedule, I would insert an impact fragnet into the schedule network to determine how much the impact affects the overall project.

    Is there a good approach to do this for changes in work that is still at the low level density?

    • Schedule Density is one part of an overall approach to completing complex projects on time. This includes a new form of contract, defined roles to manage time and design data collaboratively, and new ways to plan effectively, see:

      To answer your specific question, there is nothing to stop the project baseline (low density schedule) being updated for a major change if its more than a year in the future, if the effect of the change is closer then the medium density or high density schedule is updated – there si only ever one driving schedule and the contract deals with extensions of time. For more on schedule density see:

      • Nathan Mahlum

        Thanks for the response. Perhaps I’m missing something, but I’m envisioning the entire low density level schedule on the critical path, ergo any impact would extend the completion date.

        Do you happen to have an example schedule that I could view?

      • All of the schedules are normal critical path schedules – some activities will have float some won’t. The concept is adding ‘density’ (ie, more detail) in an orderly way based on pragmatic knowledge of what’s actually occurring.

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