The Forex trading system comes in many different guises ranging from the genuinely useful to the appallingly useless. As well as the genuine but still profitless systems that exists there are also the equally common scams from people trying to earn money for providing no valuable service. Traders who are interested in finding a profitable system will have to do their homework.
Systems are only as valuable as their results. Traders should never purchase any system or software, for that matter, that doesnt show previous results or offer a reasonable trial period to paper trade the results. Almost all genuine systems will provide some sort of credentials about the service on offer because they want to persuade traders to purchase from them. Check the website of the system in question for historical results.
As well as looking at the results themselves traders should pay particular attention to the validity of the results. By checking some of the results against the criteria of the system it is possible to verify the selections easily and quickly. In the long run, this can save a lot of heartache. A failed system wont necessarily lose an investor the money they spend...