Quote from smilingsynic:
Actually, this is where I see problems with the rule:
1. The overnight low was 37, but the daytime low was 38.50. Which low does one choose?
2. There is that gap from overnight that is just sitting up there, waiting to be filled, at 51.25. If one shorts at 47 (10 from 37) and has a 2-3 point stop, the gap gets filled and the trader gets stopped out. If one shorts at 49 with a 2 point stop, then the trader gets stopped out; if one uses a 3 point stop, well, who knows?
As I said before, the rule is a good rule of thumb, but trading cannot be boiled down to one rule. There are MANY potential places the market can go.