Tech: McClellan summ does not use any fix periods and so does vector vest. Hurst is a price based system and price is the only variable; and as such it can not tell sudden changes in momentum like in May 06 or even recent sudden drop. McL and VV are based on market breadth and are pretty good indicator of change in market direction before it happens. VV correctly predicted recent drop as their breadth indicator made a double top while on McCl the double top was more subdued. On the other hand they can not predict price points which is the strength and beauty of the Hurst sytem as practiced by Mr. Airdale and Mr. Cash and others. I am happy to see Mr. Airdale using breadth indicators more often. These two systems are not contraditory but rather complimentory