Using the Portfolio123 platform the iM-Best Gold Timer (click for more details) was backtested from Jan-2-2000, as this was the first full year when the algorithm had access to all the required economic indicators from the database of the web-based simulation platform where the backtest was performed.
The timing algorithm is partly based on my research reported in this article. The model uses the SPDR® Gold Shares ETF: GLD, and the economic indicators Federal Funds Rate, 10-year Treasury Note yield, and the S&P500 Estimated Earnings Yield. The benchmark is the Specialty Index SP1500 Gold, representing the gold miners in the S&P1500. The ETF GLD has already gained about 10% since the date of the buy signal to the middle of February-2014.
There were three buy signals: 2/20/2001, 5/11/2009 and 12/30/2013. An interesting observation is that the three buy signals always occurred shortly after the normalized benchmark index (blue graph) bottomed near 100, as can be seen from the chart above.