Quantitative structure-property/activity relationships (QSPRs/QSARs) are a component of modern natural science. The system of self-consistent models is a specific approach to build up QSPR/QSAR. A group of models of refractive index for different distributions in training and test sets compared. This comparison is a basis to formulate the system of self-consistent models. The so-called index of ideality of correlation (IIC) has been used to improve the predictive potential of models of the refractive index of different polymers (n=255). The predictive potential of the suggested models is high since the average value of the determination coefficient for the validation set is 0.885. In addition, the system of self-consistent models may be applied as a tool to assess the predictive potential of an arbitrary QSPR-approach.