CREAM was developed by E.Hollnagel based on his experience in the field of both human factors and human reliability. There are two versions of CREAM in Hollnagel’s book; one is a simplified view of controlling modes and the other is a more detailed view of human errors. Both methods have been applied in NASA study. CREAM I was applied as a screening method in an early HRA study for the International Space Station PRA and later was replaced by the HDT approach. CREAM II was applied for one of the HRA studies for the Orbiter PSA/HRA study.
Reference: Human reliability assessment: theory and practice