Depth & Non-Depth Indexing
Depth indexing means that the article is indexed in detail, covering ALL main points and significant minor points.
Non-Depth indexing means that the article is indexed with less detail and less specificity. In general, letters, news items, editorials, and reviews are indexed non-depth.
Every article is indexed completely, whether Depth or Non-Depth, the only difference is the degree of detail and specificity.