Each county and crop has a TA-APH trend rate. This rate is estimated using National Agricultural Statistical Service (NASS) county yields, with controls include for weather and spatial considerations. These TA-APH rates are county specific and are published by the Risk Management Agency (RMA). Each insured unit in a county will use the same TA-APH rate. The table in the appendix shows corn and soybean TA-APH rates for Illinois.

Table 1 shows an example of the 2012 TA-APH yield calculation for a McLean County farm having 10 consecutive yields from 2002 through 2011. The 2002 yield is 158 bu./acre, the 2003 yield is 144 bu., the 2004 yield is 182 bu., and so on. This APH yield for this yield history is 175.4 bu.

Corn in McLean County has yield trend of 2.06 bu./year. Under the Trend-Adjusted APH, each yield will be adjusted by 2.06 bu. times the number of years from the current insurance year. The further the year is from the 2012 current year, the higher is the trend adjustment. For the 2011 yield, the trend adjustment is 2.06. In 2011, the actual yield is 170 bu., and the TA-APH yield is 172.1 bu. (172.06 = 170 bu. + 2.06 trend adjustment). The trend adjustment for the 2010 yield is 4.12 bu., or the 2.06 trend times two years from 2012. The actual yield in 2010 is 186 bu. and the TA-APH yield is 190.1 bu. (186 bu. plus 4.01 trend adjustment). The above process is continued for each year in the past, and then the adjusted yields averaged to arrive at the Trend-Adjusted APH.

In the example shown in Table 1, the TA APH yield is 186.73 bu., 11.33 bu. above the 175.4-bu. APH yield.