Since much of their work consists of analyzing classified data, they may also be screening out those they decide aren't likely to obtain those clearances. Many

Since much of their work consists of analyzing classified data, they may also be screening out those they decide aren't likely to obtain those clearances. Many defense contractors hire you provisionally (and might put you on a non-classified project) but don't expect to keep that job if you wash out of the background check process. There are plenty of interview questions you could ask to avoid candidates that you know won't make it.