as megaprojects expert Bent Flyvbjerg explains in the following article, these grandiose projects operate by an iron law: over budget, over time, over and over again
Performance data for megaprojects speak their own language. Nine out of ten such projects have cost overruns. Overruns of up to 50 percent in real terms are common, over 50 percent not uncommon. Cost overrun for the Channel Tunnel, the longest underwater rail tunnel in Europe, connecting the UK and France, was 80 percent in real terms. For Boston’s Big Dig, 220 percent. The Sydney Opera House, 1,400 percent. Similarly, benefit shortfalls of up to 50 percent are also common, and above 50 percent not uncommon.