Cost of large projects

Some projects can be very large in scale. 

Major dams, power plants, industrial and commercial buildings, roads, railways and airports cost significant amounts of money. 

It is easier to hide large bribes and inflated payment claims in large projects than in small projects.

For example, if the total cost of a project is $100 million, and a bribe of $1 million is paid to public officials, it may be possible to conceal the cost of the bribe in the cost of the works, by inflating the cost of each item by 1%.  This cost inflation may not arouse suspicion, as it is only 1%, and it would be difficult to identify in the project documents. 

If, on the other hand, the total cost of a project is $1 million, and a bribe of $1 million is paid to public officials, this would inflate the cost of the project to $2 million, which is a 100% increase.  This should raise alarm bells, and be much easier to identify.