During a recent interview with Big Boy, Kid Cudi opened up about just how long the G.O.O.D. Music compilation album has been in production.  He stated that it is everyone's primary focus, now that each artist working on the album has finished with their individual projects.

Cudi stated:

"Kanye West has been plotting this project for a long, long time.  Everybody got their projects out of the way--now everybody's focused on this.  We've been working on it for months now.  Some of the G.O.O.D. Music album was recorded before Watch The Throne was established."

Source: vibe.com