Question

"what source should contracting officers use as their primary source of vendor information"

Answer 1

The answer to this question is CCR or Central Contractor Registration.  The CCR was the main supplier database intended for the United States Federal government. The CCR is the source where it collected data from suppliers, validated and stored the data, disseminated it to various branches in the government acquisition agencies.

Answer 2

The correct answer to this open question is the following.

The source should contracting officers use as their primary source of the vendor information is the Central Contractor Registration (CCR), now called System for Award Management (SAM).

CCR served until July 2012. This was the place the government used to select contractors for public projects. After July 2012, the government replaced the CCR with the aforementioned System for Award Management (SAM). COntractors that already had their information in the old database, automatically migrated to the new database.