some codes are easy to comprehend..... bullish c>mov(c,10,s) bearish c<mov(c,20,s) not much there, so back testing should be a straight forward matter..... some of the codes by patrick, jose and roy larson can intimidate me, esp once they get longer than 1 line...... then after my feeble fiddling with it, to make sure i haven't created a money monster , i'll turn back the clock to test .... have both the downloader and meta open to do this.... using the downloader, first create a copy of a security, then place the copy in another, destination, folder.... now open both the original and the copy in meta.... attached the expert or code being tested to both..... right click on the last price bar in the copies chart, select 'edit data', that brings up the data sheet in the downloader...... slowly delete days..... then compare the original security to the copy in meta for anything abnormal...... each time you delete days from the copy you'll have to save and close the data sheet in the downloader..... right click on the chart and go through the same steps to delete more days, and again close it..... all that might sound difficult but after a couple minutes it'll be old hat.... patrick has mentioned test and retest.... my coding often fails, too often, back testing has just become part of the meta fun.... h