sentences:  Divisia-type indexes have advantages over constant-base-year weighted indexes, because as relative prices of inputs change, they incorporate changes both in quantities purchased and relative prices.For example, a Törnqvist index summarizing labor input may weigh the growth rate of the hours of each group of workers by the share of labor compensation they receive.The Törnqvist index is a superlative index, meaning it can approximate any smooth production or cost function.