The Public Rangeland Improvement Act (PRIA) of 1978 established a formula for determining annual grazing fees on public lands.  The formula is adjusted annually using indices of private land grazing lease rates (Forage Value Index, FVI), prices received for beef cattle (Beef Cattle Price Index, BCPI), and cost of production (Prices Paid Index, PPI).  The formula was modified in 1986 by an Executive Order, which established a floor of $1.35/Animal Unit Month (AUM).  Past statistical analysis of the PRIA formula concluded that the only statistically valid index included in the PRIA formula is the FVI and that the coefficients should not be 1,1, and -1 for FVI, BCPI and PPI, respectively.  Regression analysis undertaken in this project concentrated on changes in the performance of the 3 indices between 1992 and 2006.  Results indicate that coefficients and significance of individual indices have changed over the past 15 years.  FVI and PPI are highly correlated, tending to increase together.  Similar to past analyses, we found that FVI is the only statistically significant index in the PRIA formula.  Cattle prices have had a negative influence on forage values during this timeframe.