The PCL-R is based on a structured interview and collateral data gathered from family, friends, and colleagues and from documents. The questions comprising the structured interview are so transparent and self-evident that it is easy to lie one's way through the test and completely skew its results. (From the book "Malignant Self-love: Narcissism Revisited" by Sam Vaknin - Click on this link to purchase the print book, or 16 e-books, or 2 DVDs with 12 hours of video lectures on narcissists, psychopaths, and abuse in relationships: http://www.narcissistic-abuse.com/thebook.html)