> (Note: The word ‘narcissist’ means egotistical, self-focused, and vain)” using a 7-point Likert scale (1 = “Not Very True of Me” to 7 = “Very True of Me”)

First, this study is clearly about me, but they don't admit that anywhere. Second, I am not a narcissist, because among all other people, I'm probably the least egotistical (I am but a modest demi-god), self-focused (the things I create are actually gifts to the world), or vain (my beauty is natural and effortless). So obviously I answered the poll with all ones, excluding myself from the training data and rendering this study pointless.