I have just stumbled on some research carried out in 2004 by the eminent trader Bret Steenbarger, into pivot points for day trading.
He tested 963 trading days on S&P index and found -
80% of the days either S1 or R1 were hit
15% " " " both were hit (range days)
Of the 80% -50% closed above or below the respected S/R end of day.
I trade DAX day trade and although I have never done statistical research, I can vouch that Steenbarger’s research seems to hold true. It works as a general rule and S1 and R1 are good targets for day traders.