Abstract: A method for automatic development of an art index from repeat sales information and single sales information comprising the steps of: exploring and identifying comparables for individual artists, ensuring that said comparables are of acceptable level of homogeneity, especially regarding tests by art analyst and statistical homogeneity, determining sets of said comparables from information about the artist and/or his/her works, wherein said comparable sets are a group of comparable art objects produced by one artist that have similarities in various attributes, such as year of work, medium, genre, size and/or valuation, correcting of price variations, aberrations and/or outliers of valuation judgements within the comparable sets by using auction catalogues and/or other external sources, reports on provenance, exhibition catalogues, news releases and/or scholarly literature concerning the specific artists and objects, reanalyzing said comparable sets by carrying out an inconsistency check visually and/or in me