514 Subfield $d - Logical consistency report:

Subfield $d contains an explanation of the fidelity of the relationships in the data set and the tests used.

Example:

514 ##$bEstimated to be 98.5%.$cVillage names compared to source map -- all match, therefore errors are possible only if source maps are incorrect.$dNode-to-line, line-to-area topological relationships maintained. Line and area attributes maintained. GRASS 4.0 program "v.support" checks topological relationships.$eAll incorporated limits shown on USGS quads were digitized.$fThe accuracy of this data is based upon the use of the source maps ... [subfield $f shortened in this example]