Figure 2

Illustration of joinpoint regression model. Annual proportions of prostate cancer late-stage cases were computed for white males 65 years and over that were diagnosed over the period 1981-2007 within Florida. The segmented regression model (solid line) includes two joinpoints (τ) that correspond to years of statistically significant changes in rate trend: 1989 and 2000. The parameters β are the slopes of the successive segments.