Historical tick data and where can I download it for free?
Many times you read about a back test report of a specific robot. Basically there is only one rule: If the tick data bar is less than 99% the back test is useless. For example, check the image below where you can see a back test with a 99.9% tick data accuracy.
As you can see the image shows a 99.90% accuracy which means that you cannot get closer to real data. In case this percentage is around 90% it seems valid, but in fact its not. Specially if you are back testing on the M1 or M5 time frame the difference can be substantial. The best website where you can sign up for a free trial and download historical tick data is eareview.net
When executing the back test make sure that you use “variable spreads”. On this website you can find a good tutorial video that explains how to use the program.
Good luck and let me know if you need any help!