PREDICTIONS OF RESIN-BONDED BRIDGE SURVIVALS, COMPARING 2 STATISTICAL-MODELS

The purpose of this study was to compare the predictive accuracy of th e standard Weibull distribution model with that of a modification, or mixture model, for resin-bonded etched-metal bridge survivals. A total of 189 bridges placed in adult patients treated by students and staff at a teaching hospital was evaluated over periods of up to 8 years. S urvival predictions based on the actual survival data accumulated in 1 989 were compared with the later survival data updated in 1992. Compar ison of the two fitted Weibull predictive curves with the life table s urvival estimates from the 1992 updated data demonstrated clearly the improved accuracy of the mixture model for predicting survivals of the resin-bonded bridges in this study.