Structure, use, and validation of the IEUBK model.

The potential impact of the effects of lead in children is a major concern. Although measurements of lead concentration can be made in a geographic area, it is difficult to predict the effects of this exposure that involve complicated biologic functions. Dynamic mathematical models that can be simulated on a digital computer provide one method of analysis to facilitate the prediction process. The integrated exposure uptake biokinetic (IEUBK) model is a dynamic mathematical model that has been discretized for execution on a digital computer. This paper is concerned with the general difficulties in validating a dynamic model of this type. A number of the general pitfalls of validating a model of this type are presented. The illustrations are of a general nature not requiring an understanding of the physiologic effects of lead on children. The concept of validating a model by comparing results to historical data is discussed. A comparison is made with traditional modeling efforts having this form of dynamic model. Also included are general mathematic concepts illustrating potential difficulties with intuitive analyses in calibrating a dynamic model.