Background and aim Comparing databases performances is quite challenging, especially they are presenting different characteristics including the quantitative and quantitative aspects acquired. The primary aim of this paper is to introduce a quantitative method for performance comparison of prediction of diseases studies using measurable parameters. Results The proposed method focuses on the following parameters: the accuracy and the number of attributes, to compute the performance index. We outline the major obstacles in terms of the construction of a comparative reliable approach, and a demonstrative case regarding the prediction of heart disease is given to validate the effectiveness of the proposed method. Conclusions Comparing performance of databases used in computer aided diagnosis should be based on objective quantitative basis, inhere presented index allows to achieve this goal, and overcome the variability found through databases. The presented methods should constitute a major tool for normalizing the comparison of databases performances, hence allowing more transparent and better evidencing databases qualities.