The appropriate rule to use is the Nth Day Rule which only buys on the lowest day of the series. The -Nth Day Rule applies for shorting extended up movesQuote from sle:
and if it does not happen on day 9, you should wait for day 10in any case, a simple excel model will prove to you that trading simply on direcitonality of N days prior is not a good strategy - while you will have good winners/losers ratio, the return from the strategy is rather low.

Quote from spindr0:
The rule of N+1 states that if the rebound doesn't occur on day 8, it might occur on day 9
Sorry, I'm only familiar with The Bronski not The Bwolinsky.Quote from rew:
Yes, I too have found that the rule of N+1 is the most reliable trading rule out there. All that's left is to decide the correct value of N. No doubt a piece of cake for bwolinsky.
Quote from trader198:
what a laugh, very amusing.
just when I read through a trading book, did not rember its name. but the book gave out an a very interesting story.
he went to pee with other traders, he saw a coin here, and his friend immediately warned and asked him to pee into another place. he feel weird about his friend's unreasonable suggestion, so when out of the batheroom, he asked why?
pee in the coin means bad luck. after 7day's drop, next day will be sunny, it is a laugh. superstitution? yes.
based on physics iternia law: if an object moves to some direction, if no resistance involved, the object will continue to move in this direction ....
that is science.