Put-Call Ratios

Many market watchers use the put-call ratio (the volume of puts to calls traded on the CBOE) as an indicator of market sentiment, arguing that it is a contrary indicator at market extremes. The two charts here show its movement intra-day on February 6, 2010 and over the last 1-year. The link here argues that there is no reliable correlation between SPY returns and the Put-Call ratio over short and intermediate horizons and that the  ratio may be a lagging rather than leading indicator.