[kakwa_]

For those projects, everybody is over-optimistic in their respective bids (some could say they are basically lying...). But that's part of the game unfortunately.

However sometimes, it can be a calculated risk, for most projects, something is provided by the client, and generally they are also late on their parts. If played correctly it can hide delays on your side.

Also, being over-optimistic in a bid doesn't mean you have to be over-optimistic internally, you could set realistic expectations internally and "manage" properly the delays on the customer front.

Just to be clear, this is a cynic view of things. Every time I see something like that, I cringe inside (and even outside).

However the 2x rule can be quite limited in big projects as it doesn't account for the overhead induced by the size. In a team of hundreds, 30, 40 or 50% of the efforts can be lost due to difficulties in communication, management layers, heterogeneous set of competencies and skills, etc. It's harder to identify what this overhead could be. They can be huge differences between relatively well integrated teams and a complete mess.