By Mark Hulbert, MarketWatch CHAPEL HILL, N.C. (MarketWatch) — Market declines rarely end with days like Thursday’s 513-point drop for the Dow.

So even if you think that we’re just suffering a mere correction within an ongoing bull market, you still should be prepared for lower prices in coming sessions.

That at least is the conclusion that emerged from my analysis of past bear market bottoms. The days on which those bear markets actually registered their final lows typically were rather uneventful — nothing like what we saw on Thursday.

via Bottoms rarely look like Thursday’s rout – Mark Hulbert – MarketWatch

That may be true but its all the more reason to selectively buy.  You won’t get the bottom.  I suggest following the Investment Survival Guide “Force yourself to buy on extreme weakness and sell on extreme strength.”  Of course you must recognize the difference of being wrong about your thesis if the facts change.