Focuses on NEW research. Didn't cover all chemical patents in early years. In some cases may rely on secondary sources. Indexers don't read original documents Chronological coverage Print CA began in 1907, electronic CA in 1967. Indexes cumulated every ten volumes.
Online abstracts have detailed indexing when added to database.
For 1350 core journals in Caplus, bibliographic citation and abstract appear in one week. Index entries added later. Cross-references used when abstract could appear in more than one section Subject sections change with time to reflect current research. Subject coverage manual gives detailed definition of each section and a table of changes over time. First sentence highlights findings and conclusions reported.