Where did the Misuse of the names Gantt and PERT Originate?


By Patrick Weaver 

Melbourne, Australia

Following on from the publication of my paper Henry L Gantt, 1861 – 1919: Debunking the myths, a retrospective view of his work [1] in the December 2012 edition of the PM World Journal, a number of discussions with colleagues has raised the questions:

  • Why are barcharts so often referred to as Gantt Charts?
  • Why are network diagrams (ADM or PDM) so often referred to as PERT charts?

My research, outlined in this paper, demonstrates that Gantt’s supposed influence on project management (outside of his involvement in Taylor’s ‘scientific management’) is an invention of the recent past. Looking back at my project management training in the early 1970s, and reading through mainframe and mini-computer manuals and early PC system manuals from the 1970s and 80s, the term ‘bar chart’ predominates, and is used uniformly in both UK and USA documentation.

Similarly, the term PERT was primarily concerned with the calculation of the probability of completing the PERT critical path by a particular date. And by the 1970s PERT was seen to be a suboptimal process for determining this probability, rapidly being replaced by Monte Carlo simulation (for more on PERT and the misuse of the name see: http://www.mosaicprojects.com.au/WhitePapers/WP1087_PERT.pdf).

When the terms PERT and Gantt Chart were used in the 1970s these terms were generally used to accurately describe the documents and processes the names were originally coined for: Gantt Charts for production control tools in factories, PERT for the calculation of probabilities using standardised formula.

Note: The conclusions in the paragraph above are based on fairly limited resources. I would be very interested to hear from colleagues if there are examples of the wide spread use of the terms from this period – all emails will be responded to.

A possible source of the current misuse of the terms.

Around 1984/5 Microsoft Project was launched and it used the term ‘Gantt Chart’ for its bar chart view and ‘PERT chart’ for its PDM (or CPM) network diagram.  Both terms are ‘wrong’ form a purist perspective, but the increase in the usage of both terms seems to correlate with the rise to dominance of Microsoft Project over many competing PC scheduling tools.

[1] Read the December paper: https://pmworldjournal.net/wp-content/uploads/2012/11/PMWJ5-Dec2012-WEAVER-Henry-Gantt-Debunking-Myths-Featured-Paper.pdf


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About the Author

flag-australiapatrick weaverPatrick Weaver       


Patrick Weaver, PMP, PMI-SP, FAICD, FCIOB, is the Managing Director of Mosaic Project Services Pty Ltd, an Australian project management consultancy specialising in project control systems and a PMI Registered Education Provider.  Patrick is also the business manager of Stakeholder Management Pty Ltd. He is a Fellow of the Chartered Institute of Building, Australasia (FCIOB) and a Fellow of the Australian Institute of Company Directors (FAICD). He is a member of the PMI College of Scheduling, and the PMI Melbourne Chapter (Australia), as well a full member of AIPM, APM (UK) and the College of Performance Management.  Patrick has over 35 years experience in Project Management.  His career was initially focused on the planning and managing of construction, engineering and infrastructure projects in the UK and Australia. The last 25 years has seen his businesses and experience expand to include the successful delivery of project scheduling services and PMOs in a range of government, ICT and business environments; with a strong focus on project management training.  His consultancy work encompasses: developing and advising on project schedules, developing and presenting PM training courses, managing the development of internal project control systems for client organisations, and assisting with dispute resolution and claims management.  He is a qualified Arbitrator.  In the last few years, Patrick has sought to ‘give back’ to the industry he has participated in since leaving college through contributions to the development of the project management profession.  In addition to his committee roles he has presented papers at a wide range of project management conferences in the USA, Europe, Asia and Australia, has an on-going role with the PMOZ conference in Australia and is part of the Australian delegation to ISO TC258.  Patrick can be contacted at [email protected] or at www.mosaicprojects.com.au.