The CIA's Center for the Study of Intelligence is one of the agency's most open branches. The in-house think tank sponsors studies on how to improve intelligence collection and analysis and publishes a respected journal, Studies in Intelligence. But since 2003, at least three unclassified CSI reports -- all critical of the agency -- have been withheld from the CIA's website. During that same time, the agency has placed online three other CSI reports, all of those relatively positive or neutral.