To be successful, the system must change the house edge into a player advantage — which is impossible for pure games of probability with fixed odds, akin to a perpetual motion machine.
Mathematically, no betting system can alter long-term expected results in a game with random, independent trials, although they can make for higher odds of short-term winning at the cost of increased risk, and are an enjoyable gambling experience for some people.
Strategies which take into account the changing odds that exist in some games (e.g. card counting and handicapping), can alter long-term results.
[1][2][3][4] This is formally stated by game theorist Richard Arnold Epstein in The Theory of Gambling and Statistical Logic as: Theorem 1: If a gambler risks a finite capital over many plays in a game with constant single-trial probability of winning, losing, and tying, then any and all betting systems lead ultimately to the same value of mathematical expectation of gain per unit amount wagered.
[1]Common betting systems include: Some horse racing betting systems can be based on pure statistical analysis of the odds, while others also analyze physical factors (e.g. the horses' form, jockey form and lane draw).