During the 1990s and 2000s, Pixar gradually developed the "Pixar Braintrust", the studio's primary creative development process, in which all of its directors, writers, and lead storyboard artists regularly examine each other's projects and give very candid "notes", the industry term for constructive criticism. The Braintrust operates under a philosophy of a "filmmaker-driven studio", in which creatives help each other move their films forward through a process somewhat like peer review, as opposed to the traditional Hollywood approach of an "executive-driven studio" in which directors are micromanaged through "mandatory notes" from development executives outranking the producers. According to Catmull, it evolved out of the working relationship between Lasseter, Stanton, Docter, Unkrich, and Joe Ranft on "Toy Story".