Table 6.20 -- EDCS Attributes whose label begins with Q
| Label | Definition | Attribute value type | EQ label | Related concepts | Code |
| QUALCHAR_RELIABILITY | The reliability of a qualitative characteristic, expressed as a fraction between zero (unreliable) and one (fully reliable). | REAL | PURE_NUMBER | 842 | |
| QUALCHAR_STDV | The standard deviation of a qualitative characteristic. | REAL | PURE_NUMBER | 843 | |
| QUATERNARY_TRAFFIC_DIR | The horizontal angle, measured in a clockwise direction from above, from planetary geodetic north to the direction of traffic, fourth occurrence. | REAL | PLANE_ANGLE | 844 |