Index creation for individually unique objects like residential real estate and art requires a different approach than used for an index of stocks, bonds and commodities. This is due to the infrequency of trading and differences in the characteristics of the objects that come to market from period to period. Thus for art and real estate an index based on average prices over a period of time may be more dependent on the mix of objects that come to market rather than changes in the underlying market itself. A database of repeat sales of the same object resolves this issue. Our database for art now has over 13,000 repeat sale auction pairs and approximately 1,000 additional pairs are included each year. We use a statistical methodology to create our index which is similar to that developed by Professors Case and Shiller for their residential real estate index published by Standard and Poor's.

To insure transparency for our art indexes we only collect data based on public auction results. We gather data continuously on the New York art market from Sotheby's and Christie's auction houses and have gone back to 1925 to start our analysis. For the major art collecting categories; old master and 19th centaury; American before 1950; impressionist and modern; Latin American; and post war and contemporary we search the current sale catalogues for items that have sold. For those items which also have a listed prior auction sale we use our best research efforts to obtain the consummated prior sale price at any auction house, anyplace in the world and at any date. If the object has been held for at least a year and we have successfully found both the sale and purchase prices including the relevant buyer's premium we include it in our database. Thus, we introduce no subjective sample selection bias. We start our current annual All Art index with data available from 1925 since that is the start date for the S&P 500 total return index which we use for comparison purposes. Our All Art index explains approximately 70% of the variability of a measure of the underlying returns of the objects on which it is based.

We intend to publish the new value of the Mei Moses® All Art annual index during the first week of January of each year. Using newly collected data, we update the index using the return estimated for the past year. (Note that, while the new data added may improve the estimates of prior years, we will not retrofit the index published before.) The year end value for 1925, the starting year for our index, was 1.0 and the 2007 year end value of our index was 279.42 and the 2008 year end value was 267.1. Information on historic performance of our indexes is available to registered premium users of this website. For customers interested in a more detailed description of the data and methodology please see our article, Art as an Investment and the Underperformance of Masterpieces, in the December 2002 issue of the American Economic Review.