Poor duration estimation a key cause of project delay

Between 2008 and 2016 the oil and gas sector embarked on some of the largest gas field to LNG project to be undertaken in Australia which, as they eventuated, suffered many delays and cost overruns.  To understand the cause of these delays, Project Forecast conducted a survey that sought the opinion of the cause of delays to the CSG to LNG mega projects being undertaken in Australia at the time.  The survey found that poor planning and underestimation of project duration was one of the top five causes of delay [1].

Project Forecast’s survey on good scheduling practices also suggests that poor estimation of project durations is one of the top three actions project planners get wrong when preparing project plans and schedules [2], a finding that ratifies similar findings by PwC in its 2014 Global PPM Survey [3], which found that one of the top two reasons for project delays included poor estimates in the planning phase.

Furthermore, Kerzner [4] in his book Project management : a systems approach to planning, scheduling and controlling states that typical reasons project plans fail is because they are planned to have too much to do in too little time and that plans are based on insufficient data.

The surveys and reports above clearly suggest that poor estimation is one of the key contributors to project delay, but how do we get it right?

Project durations can vary greatly depending on the experience and expertise of the project team, the location of the project, government and corporate influences, the changes in weather patterns and changes in local and global supply chains.

To provide some certainty, in an uncertain environment, Project Forecast has prepared, and will continue to, prepare and update, a number of project duration benchmarks to help remove some of the uncertainty and gain some assurance that the duration allowed are reasonable and can be achieved.  The project duration benchmarks include lead times, activity duration benchmarks, and project duration benchmarks. You can find out more here about our Project Benchmarks here.


  1. Interim Survey Results on CSG to LNG Project Delays. 2014, Project Forecast.
  2. Project Forecast Survey Results : Good Scheduling Practices 2016. 2016, Project Forecast.
  3. PwC, When will you think differently about programme delivery? 4th Global Portfolio and Programme Management Survey. 2014, PriceWaterhouseCoopers.
  4. Kerzner, H., Project management : a systems approach to planning, scheduling and controlling. 11th edition ed. 2016, Hoboken, New Jersey: John Wiley & Sons.