Flyvbjerg and Stewart further found that cost overrun is a persistent problem for the Olympic Games:
- The Games overrun with 100% consistency. No other type of megaproject is this predictable regarding cost overrun. Other megaprojects – in construction, infrastructure, dams, ICT – are typically on budget from time to time, but not the Olympics.
- With an average cost overrun in real terms of 179% – and 324% in nominal terms – overruns in the Games have historically been significantly larger than for other types of megaprojects.
- The largest cost overruns have been incurred by Montreal 1976
(796%), Barcelona 1992 (417%), and Lake Placid 1980 (321%), all in real
- The data show that for a city and nation to decide to host the Olympic Games is to take on one of the most financially risky type of megaproject that exists, something that many cities and nations have learned to their peril. For example, cost overrun and debt from Athens 2004 substantially worsened Greece's financial and economic crises 2008–12. Montreal took 30 years to pay off the debt from the 1976 Games.