Description of Average Annual Percent Change (AAPC) Image

This joinpoint graph illustrates how Average Annual Percent Change (AAPC) is derived from the Annual Percent Changes (APCs) during a time period.

The graph is labeled "Prostate Incidence, Males, All Races, 1975 - 2003".

The y-axis ranges from 0 to 250. The x-axis ranges from 1975 to 2003.

The joinpoints, which are the points at which the APC changes, are in 1988, 1992, and 1995.

The first APC segment begins around 100 in 1975 and increases to around 125 in 1988. The weight (which is the number of years in the segment, or the number of years the segment contributes to the AAPC denominator when calculating the AAPC for the whole graph) is 13, and the APC for this segment is 2.6 (which is significantly different from 0), with a slope of 0.026.

The second APC segment begins around 125 in 1988 and increases sharply to around 240 in 1992. Its weight is 4 and its APC is 16.3 (significantly different from 0), with a slope of 0.151.

The third APC segment begins around 240 in 1992 and decreases sharply to around 160 in 1995. Its weight is 3 and its APC is −10.7 (significantly different from 0), with a slope of -0.113.

The fourth APC segment begins around 160 in 1995 and increases gradually to around 170 in 2003. Its weight is 8 and its APC is 0.7, with a slope of 0.007.

For the period from 1975 to 2003, the AAPC denominator is 28 (13 + 4 + 3 + 8), and the AAPC itself is 2.4 (significantly different from 0).

For the period from 1994 to 2003, the AAPC denominator is 9 (1 + 8), and the AAPC itself is −0.6.

For the period from 1999 to 2003, the AAPC denominator is 4 (4), and the AAPC itself is 0.7.

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