Bears are usually early and like to short bottoms.

Some quick examples:

So July 19th P/C ratio from QQQ spiked above 1.0 right at the bottom of the down trend. Bears shorted the bottom. They have a habit of it.

Then back in April you can see P/C spiked crazy a few times and was followed by very mild down moves. The real sell off didn't come till P/C dropped. Then spikes above 1.0 signaled bottoms for the down move.

It seems $PCQI is no longer supported, unfortunately.