Talk:Critical path drag

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Created this page to describe in more depth what critical path drag is, how to compute it, and why it is valuable to the project manager. Nuggetkiwi (talk) 19:47, 6 December 2012 (UTC)

I see that this page has been marked for deletion. I'm not quite sure why. I added it as a link to the page on critical path method, to explain in more detail just what critical path drag is, why it's relevant, and, most important, how to compute it.

Just as every project schedule has a critical path (whether or not we've planned it out!) that determines its total duration, so too every activity on that critical path is adding time to the project duration, and therefore has drag. Drag, as in physics and engineering, is that which slows down an object (such as an aircraft or submarine) moving through a fluid. In a project, it is work or a constraint which slows down progress on the critical path. Since engineering projects are a major user of project management, the meaning of the term is intuitively obvious to such communities.

The references that are cited are: (1) a book by a major business book publisher that has been in the market for 13 years; (2) an article written by William Duncan, author/editor of the first edition of the PMBOK Guide (Duncan is currently Certification Chair of the the International Project Management Association's (IPMA) US Chapter ASAPM (http://www.asapm.org/PD/default.asp) and his article is published on that site) ; and (3) an article in Defense AT&L, a leading publication of the US Department of Defense's Defense Acquisition University at Fort Belvoir, VA. The Defense AT&L article means (1) that it is innovative information (otherwise such a prestigious periodical in a very mature application of project management would have rejected it) and (2) that it is now relatively common knowledge among major US Defense contractors. Additionally, this article is being re-published in a new book later this month Project Management for the Oil and Gas Industriesby Adedeji Badiru, Department Head of Systems & Engineering Management at the Air Force Institute of Technology, Dayton, Ohio, further spreading the about critical path drag metric to the energy sector. And later this year, another book by Badiru and USAF Major Leeann Racz titled The Handbook of Emergency Response Planning includes a chapter on using critical path drag to optimize emergency response.

In the construction field, critical path drag is already being used, as evidenced by the functionality for the past three years for computing drag in Spider Project, a Russian software package that is used extensively on large construction projects (dams, Olympic villages, etc.) in Eastern Europe, Asia and Brazil (listed here in their English language documentation along with their ability to compute Total Float, Free Float and Super Float: http://50.28.71.154/~archibal/images/PDFs/spider_project_datasheet.pdf). Additionally, The Project Optimizer from Sumatra.com (http://www.sumatra.com/projectoptimizer/projectoptimizer.htm) is an add-on to Microsoft Project that computes drag, and another software package that specializes in outage management is currently developing the functionality. (I have not referenced any of these packages on either the critical path drag Wikipedia page or the Project management software page as I did not know if it was appropriate. But I will do so if you tell me to.)

Here (http://www.canstockphoto.com/word-cloud-for-critical-path-method-11369946.html) is a word cloud for "Critical path method". As you can see, "drag" is in the lower right hand quadrant at approximately the same size as "float". (In a few years, I suspect it will be larger as drag is more "critical": float is always OFF the critical path and drag is always ON it. In that regard, a Google search for "critical path" and "free float" turns up 24,800 hits, while a similar search for "critical path" and "drag" turns up 137,000 hits. Some of those might be "drag and drop" rather than referring to critical path drag, but even a search of "critical path drag" all in quotes (so that the entire phrase has to be present) turns up 16,000 hits -- and that would omit all those sites which say something like "activity drag" or "drag on the critical path".

There seem also to be many courses, both university and corporate, that are teaching the concept of critical path drag all over the globe:

1. Technische Universitat Kaiserslautern in Germany, a course in Process Modeling by Dr. Jens Heidrich, slides 36 and 40 of the PDF file teach how to compute drag (http://lectures.iese.fraunhofer.de/pm/downloads/pm2012-chapter-6-planning-and-control-2-slides.pdf) 2. King Saud University in Saudi Arabia, Course CSC 443 on IT Project Management taught by Dr. Safwan Qasem, slides 47-50 of the PDF file (http://faculty.ksu.edu.sa/sqasem/Documents/CSC443/CSC%20443-%20Lecture%204-%20The%20Project%20Time%20Management.pdf) 3. A Projacs.com course in Dubai in April 2012 that advertises teaching the use of drag to reduce project duration (http://www.projacs.com/training/course-search.html?course=1447)

I am sure there are many others, especially university courses, but these are just the ones that have put their course on-line.

I am sure there are many others, especially university courses, but these are just the ones that have put their course on-line.

Other articles: 1. "ProChain Solutions: Diagnosing the Drag in Clinical Development", published in eCliniqua Magazine in 2009 by a Deb Borfitz (http://www.ecliniqua.com/2009/08/07/prochain.html) 2. "Building Construction", an architecture blog (http://buildingconstructionnotes.blogspot.com/2011/10/critical-path-method-cpm.html)

Finally, the term "drag" as applied to delays in a critical path schedule may not even be new -- there is a term "lag drag" that, if Googled with "critical path" produces articles that analyze the delay caused by the "reverse critical path" anomaly, where an FF or SF constraint on one activity that is an SS or SF predecessor of another causes "drag" and delays the critical path. Whether or not this usage precedes or was influenced by the Total Project Control book or articles is anyone's guess. You can check such articles out for yourself by Googling “lag drag” “critical path”.

I will add the eCliniqua article as a reference, and a lag drag usage reference, because they are clearly talking about critical path drag, even if they do not show how to compute it. But if you want to remove those references, I'm fine with that. Under any circumstances, I hope you will decide to keep the page, as it is explaining something that is of great importance in critical path scheduling, and something that is being used more and more.

Thank you, Nuggetkiwi (talk) 21:18, 4 January 2013 (UTC)