"The indicator is designed for use on a monthly time scale. It's the sum of a 14-month rate of change and 11-month rate of change, smoothed by a 10-period weighted moving average. "Coppock, the founder of Trendex Research in San Antonio, Texas, was an economist. He had been asked by the Episcopal Church to identify buying opportunities for long-term investors. He thought market downturns were like bereavements and required a period of mourning. He asked the church bishops how long that normally took for people, their answer was 11 to 14 months and so he used those periods in his calculation. A buy signal is generated when the indicator is below zero and turns upwards from a trough. No sell signals are generated (that not being its design)......" (Coppock Curve on Wikipedia)
First, I used it on the daily chart and saw higher lows and a 0-line cross to the upside right after the S&P March bottom. Thereafter, I saw lower highs on the Coppock Curve from March to January, 2010. The curve just made a new low below the zero line at -9.48. Not sure if there is structural significance. Just saying it could have been sensing the recent sell off like the MACD.
Chart courtesy of FreeStockCharts.com
You are really supposed to spot long term bottoms using the monthly chart. Not sure if you can tie the monthly and daily together. Here is the S&P 500 and Coppock Curve dating back to 1970 using the monthly scale. Every time the Coppock Curve reversed from a trough below the zero line it timed a new bull market. Except for the head fake in 2001. It timed the March lows nicely and made a huge swing from -75 to 20. The question is do we have to "bereave" again in a double dip? Well you know when to buy!