I don't think you can really mathematically prove if you have an edge or not like you can in, say, black jack, where based on the limited fixed number of parameters involved in a particular hand you can mathematically determine your odds of success of a given hand based on mathematical proofs. However, with markets there are just too many moving parts, and markets change behavior and nature, so systems that used to work don't work anymore after a while. This is why finding a system tailored to how you interpret markets is most important. As your interpretation of markets changes, your systems will change too. For example, my research shows that crude oil tends to panic better to the upside more than to the downside, yet stocks trade better to the downside during panics. So, how I trade panics, large moves, increases in volatility, etc. is different for different markets. Someday, those beliefs may not play themselves out that way anymore and I'll have to adapt my opinions and use different systems, or at least different versions of current systems.