Talk:Goldman Sachs Commodities Index

I read recently that the Goldman Sachs Commodity Index was a useful indicator to predict recessions. The statement was "Anytime the index increases by 50 percent, a recession followed." The article was very brief and vague and did not specify the time required to rise 50 percent or how quickly afterward a recession ensued. I have tried searching the web to find a more detailed discussion, but have come up empty. Can anyone elaborate on this indicator? Was the statement just rubbish or was it based on a serious study?