That I thought, Pythonized: upw = dtr==false and dtr[-1] and utr dnw = utr==false and dtr[-1] and dtr Meaning upw is true if current dtr is false and utr is true and the previous dtr is false. This would mark an upward trend change. The same upw = (not dtr) & dtr[-1] & utr dnw = (not dtr) & dtr[-1] & utr In Metastock: Assignation := Comparison =