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CPM Schedule full of flaws?

8 replies [Last post]
Tue, 2003-06-03 04:26
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Dear all,
We received this message from someone in Hong Kong. I wonder if you guys can comment on it.

Regards,
Robert Cunningham, Hong Kong/Taiwan/Singapore/Malaysia

I am sure that the following guys will have a lot to say on this:
David Bordoli - Hong Kong
Clive Holloway - Hong Kong
Ronald Winter - US
Ed van der Tak - Holland
Paul Harris - Doncaster East, Australia

Critics Cant Find the Logic in Many of Todays CPM
Schedules
(5/26/2003 Issue)

Users want software with flexibility, but is it true
CPM?

By Richard Korman with Stephen H. Daniels

(edited by moderator - please do not post copyrighted articles in their entirety. Post a snippet and a link to the original source.)

(snippet)
One of the reasons for starting the college is
disconcerting. What is described as a CPM schedule
these days sometimes isnt one at all, the four
experts claim. If that claim is true, it says a lot
about how personal computers have transformed
scheduling and what could be in store as technology
reshapes other phases of the construction process.

At the meeting, the four experts lamented the state of
scheduling. They say they see widespread abuses of
powerful software to produce badly flawed or
deliberately deceptive schedules that look good but
lack mathematical coherence or common sense about the
way the industry works. The result is confusion,
delayed projects and lawsuits.
(/snippet)

Critics Can’t Find the Logic in Many of Today’s CPM Schedules
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Replies

Wed, 2003-07-09 14:38
#1
Bernard Ertl
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As of this point in time, 91% of those polled think that the lack of transparancy in the critical path in PDM schedules is a big problem:

PMI College of Scheduling - PDM/Critical Path Poll

I have personally seen instances where PDM schedules obscured important information and displayed incorrect results. Unless every project manager is going to audit the data itself, transparancy is necessary to ensure the integrity of the schedule.

Bernard Ertl
InterPlan Systems Inc. - Project Management Software, Project Planning Software
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Wed, 2003-07-09 03:42
#2
Alan Binnie
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Having viewed the original article and the subsequent letters posted in ENR, I would disagree that the schedules are flawed, however they may not be perfect plans in terms of pure planning principles. But I think that planning software provides the ability to better reflect reality, for example multiple calendars, progress override etc.

What must always be remembered is that the software is a tool and how reliable the plan is will depend on the ability or skill of the planner, together with other influences such as the project manager or company requirement, or the clients requirement etc. as mentioned by some previous posts. Planning software not only allows much greater reality to be built into a plan, but allows a programme to be produced much more quickly than by manual means which gives the planner more time to actually analyse the work content which is being scheduled instead of actually drawing the network and/or barchart.
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Mon, 2003-06-09 00:49
#3
Mark Lomas
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Very intersting article and views, guys.

A key to maintaining the integrity of the scheduling "profession", is for those who demand (and pay for) schedules, to be aware of the tricks. A client / PM / project sponsor shouldnt accept a schedule if it is just a pretty bar-chart. If you dont get the soft copy, how can you see what is buried within ?

If the market then demands integrity, it will have to be delivered. If not, then P3 does produce some very pretty bar charts ! PMs take action.
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Tue, 2003-06-03 14:54
#4
Tomas Rivera
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Regardless of how bad or good software packages are, we are talking about the capacity or ability to design good schedules. We are talking about knowledge, training, learning, experience, and expertise in general.

Also, as the software provides more scheduling features, flexibility, better routines, power reporting and better options for analyzing and revising your schedule, you will be able to develop a schedule with better quality.

We will always have flawed schedules. We will find good and excelent schedules now and then. It is the same in all walks of life. It is hard to find someone who does a really good job.

What will happen? Well, we as an industry, will tend to better the quality of our schedules as the forces of the market pull us. As the construction industry (including owners)is more knowledgable and competition keeps being though, we will demand more from our project management abilities in general, and demand more from our scheduling abilities in particular. We will demand better schedules, we will regulate them more, we will give a much more use of schedules in contract agreements, we will draw the attention of everybody to the construction schedule.

What to do? We as individuals can push the advancement of scheduling practices in two ways. One is to acquire more knowledge through training, controlled experience, researching and innovation. We also need to train owners of construction projects at a high level of project management. Second, vendors are giving us a great deal of help with better tools. Whether these are dangerous or not, we need to use them properly; that is our responsability.

As a last thought, the more you advance into scheduling as well as project management, it gets to be more an art than a science. When you feel you are getting to this point, you start savoring the joy of creating schedules that resemble the true nature of the ever changing construction environment. Something happens or ceases to happen, and your schedule instantly reacts with a true response. Something changes, and your schedule gives you the real impact. You do not have any more a simple schedule, you have a decision making tool, which will drive most of your decisions. The more detailed your schedule the closer you can get to reality, and the closer you will get to your everyday decisions, not just your strategic decisions. Flawed schedules? It starts to become a thing of the past.

Tomas Rivera
Altek System
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Tue, 2003-06-03 10:24
#5
Paul Harris
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The problem I have had with creating, updating and reviewing schedules is that is it is not possible with most commercial software packages, such as P3e, SureTrak, P3 or MSP, Timeline plus a few others, etc to easily add comments, types or history to relationships.

Gigaplan does have the facility to make a relationship inactive which is the only package I have come across which allows an attribute to be assigned to a relationship.

I categorize logic links as:
1. Hard logic, such as the hole has to be built dug before the hole is dug.
2. Sequencing Logic, e.g. which hole is to be dug first, it does not matter, but only one at a time can be dug if only on digger is available, some one makes a decision. (one could level but lets leave that one out for the moment)
3. Committed Logic, the first is dug and therefore the quickest way is to dig the one next door.

I have also hear of other terms such as "Preferred" and "Soft" logic etc.

I do not think a reviewer is able to make meaningful comment on a schedule when it has a large content of soft logic, unless the reason for the soft logic documented so it may be understood. Usually soft logic is added to smooth out resource requirements or to provide a logical work flow through. Any number of solutions with different soft logic could provide a satisfactory programme.

Most of the dialogue that I have read on CPM flaws do not consider the issue of the relationship type which is one of the key elements of a CPM schedule.

The schedule may not be "Full of Flaws" when the reason for relationships are understood. It is difficult to document relationships and in terms of why they were originally entered, added or deleted in most modern scheduling software. So schedulers have to make do with Activity Log fields or Text Columns to document relationship history which is not the best way to do it.

Now to leveling (or levelling in British English), when a schedule is to be resource levelled the method of construction is very different. Soft logic is replaced by priorities and the number of activities on a critical path will change and the amount will depend on the software and levelling options selected. At this point in time a schedule is resource driven, and like so many schedules with a large content of soft logic, the schedule is not a CPM schedule but a Resource driven schedule.

I also see many schedule with missing drivers such as schedules which do not have important procurement items or approved design availability and the Critical path is meaningless with out all the important schedule drivers. These in my opinion are "Flawed" schedules.

I hope this provide food for thought.

Regards
Paul E Harris
www.eh.com.au
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Tue, 2003-06-03 09:35
#6
Bernard Ertl
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Im not sure that posting a copyrighted article in its entirety is wise. PP mods should probably edit that post. The original article is located here:

ENR.COM - Critics Cant Find the Logic in Many of Todays CPM Schedules

Many of the topics covered in that article are currently being discussed on the PMI College of Schedulings Forums:

Multiple Calendars

Progress Override

Does your schedule pass the tests?

This article made my day. We have been warning our clients for years about the potential pitfalls outlined in the article.

Incidently, I do not fault Primavera (or any other project management software vendor). Mr. Faris is correct. They are in the business of selling software and not policing or enforcing standards.

Companies that are serious about project management as a tool for managing will police themselves. Those who pay PM lip service deserve what they get. Im glad that ENR has let the cat out of the bag. Perhaps some companies will re-examine just what they are doing and improve their processes. One can hope, anyway....

Bernard Ertl
InterPlan Systems Inc. - Project Management Software, Project Planning Software
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Tue, 2003-06-03 06:47
#7
Steven Oliver
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I have always assumed that the software is a tool (whatever software that may be), in the same way as an artist has a brush. How effectively the tool is used depends entirely upon the abilities of the Planning Engineer.

I would like to think that I would produce the same plan with pencil and paper (although I wouldnt like to regress to that) as I would using computer and software. The latter option just makes me many times more efficient.

Irrespective of the tool, the thought process using it should be the same.
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Wed, 2003-06-18 16:55
#8
Ronald Winter
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ENR has posted Letters To The Editor in the latest edition of ENR responding to the original "Full of Flaws" article. Heres a link to those letters.


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