There were seven projects in our sample which had substantial construction phase scope changes where the cost was borne by the Procuring Authority. These were located across North America, Australia and Europe, and were all in the transport sector, however this may be a reflection of the greater availability of data in these regions. The values of these changes were high compared to the capital value of the project, with each example over USD $5m and one example valued at over USD $150 million. This again is likely to be reflective of the availability of information; small variations and changes were less likely to be picked up during our data collection process.

As the construction phase changes investigated were substantial, they were all associated with extensions of time, mostly for the entire portion of time delay. The majority of the changes were instigated soon after financial close, with six occurring within the first year.

There were less scope changes during the operations phase found in the study, and most were related directly to changes during the construction phase (i.e. the additional costs were due to different maintenance requirements).