| 摘要 |
The present invention comprises estimating a price index in which both quality improvement and first-product effect are taken into account, and influences exerted by replacement of an old commodity with a new commodity are reflected. The present invention is provided with: a sales database in which daily sales amount and sales quantity per commodity ID are stored; a means for acquiring the sales of a commodity set at a first point of time as first sales; a means for acquiring the sales of a commodity set at a second point of time as second sales; a common commodity extraction means for extracting, as a common commodity in a narrow sense, a common commodity that is present at both the first and the second point of time and that does not have the first-product effect, the common commodity being extracted in accordance with the duration τ of the first-product effect; a means for acquiring the sales of the common commodity in the narrow sense at a first point of time as third sales; a means for acquiring the sales of the common commodity in the narrow sense at a second point of time as fourth sales; a means for calculating a price change of the common commodity in the narrow sense and acquiring a first price index; a means for converting the second sales/fourth sales to a price ratio by using a coefficient based on the elasticity of substitution, and acquiring a first price ratio; a means for converting the third sales/first sales to a price ratio by using a coefficient based on the elasticity of substitution, and acquiring a second price ratio; and a means for correcting the first price index by adding the first and second price ratios to the first price index, and acquiring a second price index. |
