The neglect of silent evidence is endemic to the way we study comparative talent, particularly in activities that are plagued with winner-take-all attributes. We may enjoy what we see, but there is no point reading too much into success stories because we do not see the full picture.
Taleb, Nassim. The Black Swan (p. 103). Penguin Books Ltd. Kindle Edition.
Many self-help books are filled with single examples of people "who made it." The question is, which of them made it simply because of luck? How can you evaluate it in order to decide if it's worth following their example?
One way is to test it through a low cost experiment.
Another way is to widen your research and search for people who did the same and determine if they have achieved similar results.
Another way is to learn about people who did the opposite—what were their results, were they also opposite?
Another way is to use first principles thinking.