Design discussion | Comprehensive design discussion with excellent discussion of requirements, influences, reasoning, design & usability principles, with references | Very detailed design discussion with very good discussion of requirements, influences, reasoning, design & usability principles, with references | Thorough design discussion with suitable discussion of requirements, influences, reasoning, design & usability principles, with references | Adequate design discussion with good discussion of requirements, influences, reasoning, design & usability principles, with references | Inadequate or incomplete design discussion with little or no discussion of requirements, influences, reasoning, design & usability principles, with few or no references |