yi = log10(price of the ith artwork at second sale)

• yi = log10(price of the ith artwork at second sale)

• - log10(price on its first sale date)

• Independent variables consist only of dummy variables, one for each time period in the sample except for the first.

• For each artwork, the dummy variables are zero except for the dummy corresponding to the second sale, where it is +1, and for the dummy corresponding to the first sale, where it is –1.

• The estimated coefficients are then taken as the log price index.