I'm not convinced that because someone is born early in the year they will be more successful than someone who isn't. I can be more easily convinced that a person's environment has an undue influence on their home life, but not their date of birth. There are multiple factors that lead to success, including study, training, encouragement, rest, and more. However, in the context of Gladwell's book, Outliers, and the arguments he made, I think Outliers is good science because it seems to challenge the fact that Outliers are not that unique