0—May Not Be a Problem	1—Cosmetic Problem Only	2—Minor Usability Problem	3—Major Usability Problem	4—Usability Catastrophe
Visibility of system status
Match between system and the real world
User control and freedom
Consistency and standards
Error prevention
Recognition rather than recall
Flexibility and efficiency of use
Esthetic and minimalist design
Help users recognize, diagnose, and recover from errors
Help and documentation