The paper presents a method for estimating sex bias related to the quantification and weighting of compensatory factors. The method derives from the rational demarcation of the admissible ways in which the factor anchors and, hence, the raw factor scores may be quantified and aggregated to a global worth score. The demarcation process, called the model-based approach to job evaluation, is illustrated on a set of 10 jobs. Also, it is shown how the approach can be extended to the calculation of a discrimination index. The significance of the procedure for the actual practice of job evaluation as well as its potential for addressing the comparable worth issue are discussed in the closing section of the paper.