Improbability of Large Project Success


Bob Prieto

Princeton, NJ, USA

In his book, “The Improbability Principle” (1), David Hand, former president of the Royal Statistical Society provides a tour de force treatment of uncertainty and how improbable events happen, over and over again. For those who have not read it I highly recommend it.

In this paper I will attempt to use the lenses described by David Hand and look at the world of large projects and their unacceptably high failure rates. Application of “best practices” would suggest these failures should be improbable or at least less frequent than reported failure rates suggest. If we are to repeatedly experience the improbable it is perhaps better that we understand it.

The Lenses

The lenses developed by Hand can best be described as comprising a set of “laws” he has compiled to describe why seemingly improbable outcomes may not be as improbable as they first seem. These laws include:

  • Law of inevitability – something must happen
  • Law of truly large numbers – with a large enough number of opportunities, any outrageous thing is likely to happen
  • Law of selection – you can make probabilities as high as you like if you choose after the event
  • Law of the Probability Lever – slight change in circumstances can have a huge impact on probabilities
  • Law of near enough – events that are sufficiently similar are regarded as identical

Let us consider each in turn and how they shape our views on the failure of large projects.


To read entire paper (click here)

About the Author

bob prietoBob Prietoflag-usa

Senior Vice President


Princeton, NJ, USA

Bob Prieto is a senior vice president of Fluor, one of the largest, publicly traded engineering and construction companies in the world. He focuses on the development and delivery of large, complex projects worldwide. Bob consults with owners of large capital construction programs across all market sectors in the development of programmatic delivery strategies encompassing planning, engineering, procurement, construction and financing. He is author of “Strategic Program Management”, “The Giga Factor: Program Management in the Engineering and Construction Industry” , “Application of Life Cycle Analysis in the Capital Assets Industry” and “Capital Efficiency: Pull All the Levers” published by the Construction Management Association of America (CMAA) and “Topics in Strategic Program Management” as well as over 500 other papers and presentations.

Bob is a member of the ASCE Industry Leaders Council, National Academy of Construction, a Fellow of the Construction Management Association of America, a member of the World Economic Forum Global Agenda Council and several university departmental and campus advisory boards. Bob served until 2006 as a U.S. presidential appointees to the Asia Pacific Economic Cooperation (APEC) Business Advisory Council (ABAC), working with U.S. and Asia-Pacific business leaders to shape the framework for trade and economic growth and had previously served as both as Chairman of the Engineering and Construction Governors of the World Economic Forum and co-chair of the infrastructure task force formed after September 11th by the New York City Chamber of Commerce. Previously, he served as Chairman at Parsons Brinckerhoff (PB). Bob can be contacted at [email protected].