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GAO is Wrong


Activities have hundreds of fields and many might still be active if you only change a few.


GAO Schedule Assessment Guide Best Practices for Project Schedules suggests keeping deleted activities and logic while setting duration to 0. See page 140 of 240.

GAO is wrong, leaving deleted activities as well as leaving the original logic in place is not best practice:

  • It is a poor workaround used when your software is incapable to show activities in included in one schedule version but not in another.
  • I am not surprised with GAO recommendations as they are biased in favor of software incapable of dealing with comparison of schedules with deleted activities.
  • Leaving deleted activities can distort cost loading if you if you miss to delete any fixed cost assignment.
  • Leaving deleted activities can be confusing and misleading
  • Incoming/outgoing remaining lags might need to be adjusted, mere change in activity duration do not tackle this issue.
  • Leaving deleted activities can lead to wrong logic; it is a lazy scheduler approach.

Spider Project allows you to display deleted activities on a conspicuous way when comparing schedule versions and without the risk of interfering with current schedule. Easy, everything is transparent, no need to tweak schedule versions. If your software lacks enough functionality it is no excuse to promote such misleading and error prone practice.


If using a database you can

If using a database you can keep old schedule versions, as you should, this do not erases the history just clear them where not needed, where keeping them is a nuisance. Just compare new version against older versions and show deleted activities, cannot be any easier. Do you mean P6 cannot compare activities existing on different updates if activities are deleted?  If so then transfer the data to a better designed database. Even Excel can make it. Not all CPM software is so poorly designed.

GAO says - In general,

GAO says - In general, estimated detail activity durations for near-term effort should be no longer than the reporting period established by the program.

WRONG - Activity duration shall take whatever it needs to be in order to get better schedules. Duration of most activities is determined by the volume of work and resource production rates, there is no need to split activities to know progress, it is a lie, do not be lazy and measure volume of work done.

Artificial splitting of activities is wrong and might lead to undesired intermittent work under resource leveling. Trying to solve the issue using activity priorities will not always work.

Before leveling it looks like equivalent models. 


After leveling they are not always equivalent.


GAO says - The WBS is the

GAO says - The WBS is the basis of the program schedule and defines what is required as a deliverable.
WRONG - It is a well-defined scope of work (usually as per contract documents) and the means and methods necessary to deliver that defines what is required.

That there should be only one

That there should be only one WBS for each program, and it should match the WBS used for the cost estimate and schedule so that actual costs can be fed back into the estimate with a correlation between the cost estimate and schedule is absurd.  

A WBS is nothing more than an organization or grouping scheme. There is no such thing as the ideal WBS. What a client might have in mind about WBS might be different to what a contractor might need.

Some commercially available scheduling software allows for multiple WBS structures, this solves any issue between client and contractor as there is always room for both.  

GAO is wrong in perpetuating the idea of a single WBS.

That the critical path should

That the critical path should be free of lags because they obfuscate the identification and management of critical activities is absurd. Links with or without time/volume lag can be part of the critical path. Without links you are essentially drawing a Gantt chart. Same as some activities can be on the critical path, some links can also be on the same critical path, critical links can be easily identified at the links table and most software allows you to thicken critical links similar to painting in red critical activities.

When GAO says “Moreover, if

When GAO says “Moreover, if the critical path is missing dependencies or has date constraints, lags, or LOE activities or it is not a continuous path from the current status date to the finish milestone, then it is not valid.” they are in abysmal error.

There is nothing wrong with discontinuous critical path(s) if the lags, calendars and contractual milestones date constraints are correctly used.

GAO supports the archaic theories of “longest path” that breaks down under constraints other than predecessor/successor logic.

GAO suggestion to split activities as to eliminate the need for lag or to avoid long duration activities can make an activity discontiguous or intermittent when resource leveling. Activities competing for the same resource might delay the splits by leapfrogging the resources.The result is frequently a poor schedule.

GAO got most of its preaching

GAO got most of its preaching about lag wrong, very wrong: When GAO claims there is no effort or resources are associated with lag they are misleading the scheduler. They are not aware of volume lag concept and preach their old fashioned theories based on 1960’s CPM models.

GAO is right with regard to time lag that represents the elapse of time. Time lag happens when the elapse of time is independent of predecessor activity progress.

On the other hand volume lag is dependent on the progress of predecessor activity. Most lag is related to the progress of predecessor activity and therefore it is volume lag. Volume lag shall not be modeled by an activity because the progress is not on itself but on predecessor activity. Schedulers that do not know about volume lag use time lag as if volume lag, this is wrong and might lead to poor schedules.

Say pipe installation must start after 50 ft of excavation are done; it is not about time but about volume of work done by predecessor (excavation). That some passage of time elapsed do not necessary mean required work have been done. In such cases a good model will use volume lag not time lag.

GAO and many schedulers are still using old theories of the 1960's instead of using better and more modern models.

In next reference, figure

In next reference, figure black bars belong to COMPARISON schedule; Termite Treatment has only black bar and data for comparison schedule. Termite Treatment has no current schedule data, otherwise would be misleading.


A few years ago I was

A few years ago I was involved in a Vocational School Job; a building was re-designed due to unforeseen soil conditions. Everything changed, hundreds of activities no longer valid to be deleted.

A HUGE CLUTTER when dealing with portfolios of many jobs.

Why the urge to keep hundreds/thousands of deleted activities? Such clutter is unnecessary.

You keep the necessary

  • You keep the necessary records in the baseline schedule, no need to clutter the schedule; nothing is ever lost but kept in their proper database location.
  • At some point the activities must be actualized with some progress, otherwise retained logic will distort the schedule beyond comprehension.
  • In a properly developed CPM schedule all activities are part of a chain even if start-activity-finish.
  • It is as easy as 1-2-3 to prevent duplicating activity ID’s by simply adding a unique prefix/suffix to new activities for every schedule revision.
  • If the data is stored on baseline table auditing is no issue.
  • Do you mean P6 cannot compare activities existing on different updates if activities are deleted?  If so then transfer the data to a better designed database. Even Excel can make it.
  • Not all CPM software is so poorly designed.
  • Keeping deleted activities as milestones will make project statistics useless, number of activities will distort the statistics.
  • How many rules and exceptions are you going to suggest?
  • There are too many fields related of activity records that can distort the schedule that the only safe way to prevent the milestone to impact the schedule is to delete them.

I do not trust GAO as to suggest anything.  Unfortunately many will copy-cat GAO and some will go to the extreme as to declare it a standard to be strictly followed as a contract requirement.

Mr. Davila Don't necessary

Mr. Davila Don't necessary agree with your arguments here. As is customary in most planning software it's database based and removing records is not the process I've used on managing databases or projects. Normally for deleted activities I'd adopt the following process in Primavera. 1) in activity name, at start of name type "DELETED_" 2) if deleted activity has budget, then determine where it needs to be transferred to. 3) if deleted activity is part of a chain of activities reattach logic to undeleted activities as necessary, then remove logic ties from deleted activity. 4) Change duration of deleted activity to zero 5) log all steps and information into the "Schedule Changes Register" Deleted activities will ride the data date and will show up on the schedule log as errors, which can easily be discarded as they all start with the same descriptor "DELETED_". The plus side is that the chances of having a deleted activity ID reused is not possible. Why do I do it? Apart from the auditability aspect, a long time ago a software programmer that did enhancements on systems I worked on, sat me down with a list of requests we had to change particular parts of the package. He went on to explain the reasons why/why not to make some of the changes, and worked me through the steps, asking did I really want to do this and that, so it gave me a different perspective to dealing with databases. Now, the GAO might have some of the steps incorrect, and this could be fixed by demonstrating to them what the correct method is. I can see that already there are two processes, your one and mine - which one is correct'? Are they both correct'? I'm sure the people at the GAO had several versions to review, but in case they didn't it is definitely worth raising your issue with them and providing a solution.

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