My inquiry has the intent to understand your beliefs, not offend them. Please keep this in mind. As for myself, I'm in academic finance, and I believe in a somewhat strong market efficiency with the exception of a few ever present cases, that are inherently, ever changing. I've acquired these from the extensive empirical research done by myself, and by my peers. I'm very curious as to why some do not adhere to various portfolio strategies that are based around somewhat efficient markets. With the enormous amount of academic and industry research that supports the idea of efficient markets, why do some reject the evidence presented? Personally I think ones belief can reside in of of many choices, but I find the most respectable to be those who have empirical evidence collected and tests run against the idea of market efficiency. The others I have noticed are usually some sort of mix of misinterpreting personal accounts of survivorship bias as the only empirical evidence needed and/or outright rejection of respected empirical evidence without justification. I want to hear what traders here think of such ideas.