The Pentagon yesterday released additional details about a program to compile a database of personal information on U.S. students to help bolster recruitment, saying that 12 million names currently are on file and that collection efforts have been going on for some time.

David S. C. Chu, undersecretary of defense for personnel and readiness, said the Pentagon's contract with a private marketing firm was simply an attempt to obtain the most accurate list possible of contact information for high school students ages 16 to 18 as well as all college students.

In an official notice filed last month, the Pentagon said it was contracting with BeNow Inc., a Wakefield, Mass., firm that specializes in gathering and analyzing data from a variety of sources to target potential customers based on their personal profiles.

The Pentagon said information in the database could include Social Security numbers, birthdates, grade-point averages, ethnicity, e-mail addresses and subjects students are studying. The database is an amalgam of information collected from the Selective Service System, state driver's license records and data purchased from other commercial brokers.

That system angered privacy advocates, who said the government was inappropriately using a private firm to gather data on young people so they could be pinpointed as likely candidates for enlistment.

Chu said BeNow was responsible for managing the list so that it was complete, free of duplication and scrubbed of names of individuals who do not want to be contacted by recruiters.

"This is not targeting" by using personal profiles, Chu said, adding that the military has purchased data from commercial data vendors for some time. Chu said he did not know why a firm that specializes in targeted marketing was hired for the task. He said that decision was made by another Pentagon contractor, Mullen Advertising Inc., which works on military ad campaigns.

According to the Associated Press, department spokeswoman Lt. Col. Ellen Krenke said, "The program is very important because it helps the recruiters be more effective to target qualified candidates for specific missions."

Chu said the military has been consolidating its recruiting lists since 2002 to make the effort more efficient.

"You have to give the DoD an avenue to contact young people" to recruit them, Chu said, adding that the country does not want to resort to a draft.

As enlistment has dwindled in several of the services, many parents say military recruiters have become more aggressive, often calling their homes repeatedly.

Under the 2002 No Child Left Behind Act, public high school districts are obligated to provide student contact information to military recruiters or risk losing federal funds.

Despite the push to consolidate the Pentagon's recruiting lists, Chu said that the data collected from local school districts would not be incorporated into the database managed by BeNow and would be used only by local recruiters.

Chu said that Social Security numbers are "scrambled" to help thwart the potential of identity theft and that the numbers are used only to eliminate duplication and to verify requests for removal from the recruiting lists.

BeNow referred all questions about its work to the Pentagon.

Chu said the department made enough changes to its data program as far back as 2003 to warrant a notice in the Federal Register, though the notice was not posted until last month.

He said lawyers advised the department that shifting management of the program between units in the Pentagon should have triggered notice earlier.

David S. C. Chu, undersecretary of defense for personnel.