The Christmas Price Index chose the items in the popular Christmas carol "The Twelve Days of Christmas" as its market basket: a partridge in a pear tree, two turtle doves, three French hens, four calling birds, five golden rings, six geese, seven swans, eight maids, nine dancing ladies, ten leaping lords, eleven pipers, and twelve drummers.
The "Christmas Price Index" is calculated by adding the cost of the items in the song.
The "True Cost of Christmas", however, is calculated by buying a partridge in a pear tree on each of the twelve days, buying two turtle doves from the second day onward, for a total of 22 turtle doves, etc., for the complete set of 364 items.
The "True Cost of Christmas," which accounts for all 364 items, reached an all-time high of $209,272, a 3.6% increase from the previous year.
Like other lighthearted economic indicators, such as The Economist's Big Mac Index which tracks the price of the Big Mac hamburger in different countries, the Christmas Price Index nevertheless produces results which have meaningful interpretations.