Table 2.

Goodness-of-fit statistical values

IncidencePrevalenceDialysisFunctioning TransplantWaiting for TransplantMedicare Cost ($, in millions)
Model 1Model 2
a The mean error indicates an average difference (1982 to 1997) of the forecasted values from the observed values. Largest and smallest errors indicate one of the 16 yr (1982 to 1997) that exhibited the largest or smallest deviation of the forecasted value from the observed value. A positive sign indicates overforecasting, and a negative sign indicates underforecasting.
b The mean percent error reflects a proportional deviation of the mean error. Largest and smallest percent errors reflect proportional deviations of the largest and smallest errors, respectively.
c The correlation coefficient indicates the correlation between the observed values and the one-step-ahead forecasted values.
Mean errora740.0012344−0.0050.0030.0016
 largest error (residual)4135172277603331782625236
 smallest error (residual)−2365−1985−1750−4256−672−851−126
Mean percent errorb0.25−0.031.03−0.030.06−0.11−0.12
 largest percent error19.234.382.903.566.375.634.84
 smallest percent error−5.76−3.83−2.18−3.60−3.35−6.16−2.99
Correlation coefficientc0.99550.99810.99950.99910.99990.99870.9993