NSA collects only about 20 percent of phone metadata

Government sources say that the NSA's phone metadata collects only a fraction of calls, owing to the program not collecting most cell phone call records.

Reports are emerging today, citing knowledgeable sources, that the National Security Agency's phone metadata program collects the metadata of only a fraction of all calls in the United States. 

The Washington Post says the number is "less than 30 percent" while the Wall Street Journal puts it at "about 20 percent or less".

The disclosures appear aimed at lessening concern over the program, which has given many the impression that the government collects data on all calls. At the same time, it raises questions of the usefulness of the program.

The main reason for the gap in collection is that the program does not collect metadata from the calls for most cell phones. The initial reports last June of the metadata collection program noted that neither Verizon Wireless nor T-Mobile were covered under it, and speculation at the time cited the fact that both companies have substantial foreign ownership. The Washington Post story cites US officials as denying that this is the reason.

The main reason, say the officials, is the difficulties in keeping such a large database with such high input volume running. The process of putting records into the database is not a simple one and takes time as well. Compounding the difficulties are complying with minimization rules imposed by the Foreign Intelligence Surveillance Court (FISA).