When we've had very few sell signals (bottom quartile), the next 3 days in SPY have averaged a gain of +.26%, compared with a -.01% loss for the remainder of the sample. Over a next 10-day period, however, when we've had many sell signals (top quartile), the next 10 days in SPY have averaged a gain of +.52%, compared with an average gain of +.09% for the remainder of the sample.

Overall, the percentage of variance in daily sell signals accounted for by buy signals is only about 10%. They indeed are more independent than one might expect. It is in the interplay of waxing/waning buying and selling that we can sensitively track cycle dynamics.