There are plenty books and sites which offer automatic trading strategies (robots) and claim they are very profitable. On the other hand many people do not believe in such things, saying that: if there would be "graal" that generates stable profit, then the details would be kept in secret, and many other reasonable doubts in such claims.
So what is the truth ? Does most/average automatic trading system lose money in say one year/ 3 years ? or may be they win 100% in a week :) ?
More seriously: I am interested to find some analysis that would take several trading strategies and test it on various historic data and describe the results. It is better that strategies would be simple/standard and invented by third party in order to avoid conflict of interets.