The purpose of this paper was to develop and test an empirically based system to estimate the effectiveness of caries-preventive agents. Using accepted statistical methods, effectiveness predictions for fluoride supplementation, APF gels and solutions, and fluoride varnishes were calculated and used to illustrate the statistical formulation. The resulting predictions were then compared to commonly cited estimates of reduction for the respective procedures. The proposed system could be useful to public health administrators in determining the cost-effectiveness estimates for various preventive programs.