Estimating Farm Equipment Depreciation: Which Functional Form Is Best?
利用16年拍卖数据，比较多种函数形式对17种农机折旧的拟合与预测效果，发现Box-Cox函数最佳，但双平方根函数等简单方法表现接近，为实务预测提供了简化估计。
Farm equipment depreciation has been the focus of research in economics and engineering for more than 60 years. Using data from 16 years of auction sales, depreciation functions were estimated for 17 types of equipment, including tractors, combines, swathers, planters, discs, and trucks. The Box—Cox function did the best job of explaining variability in these various sales data bases and in forecasting prices in an out‐of‐sample data set. Nevertheless, the much less complicated double square root and sum‐of‐year's digits functions performed nearly as well. Simplified double square root estimates are provided for practitioners interested in forecasting equipment depreciation.