- Failing to state assumptions clearly.
- Ignoring costs due to disruption during construction
- Showing ‘optimism bias’ in demand forecasts; project costs; downside risks
- Not accounting for full costs of base-case (or ‘do-minimum’) option.
- Double counting benefits, eg increased land values due to better accessibility
- Ignoring the costs of items simply because they do not have been paid in cash, eg opportunity costs of existing land