Capital Heterogeneity: Does It Matter? Fundamental Q and Investment on a Panel of Italian Firms
利用意大利中小企业面板数据，区分设备与建筑两类资本品，用基础Q方法检验凸调整成本假设，发现标准模型适用于设备但不适用于建筑，后者存在非凸性。
In this paper we study the determinants of investment decisions at the \nfirm level with heterogeneous capital goods. We exploit a newly \ndeveloped panel dataset of small and medium-sized firms which allows \nus to distinguish between purchases, sales, and net acquisitions of capital \ngoods. We distinguish between equipment and structures and test the \nassumption of convex adjustment costs. Since our firms are mostly \nunlisted, the standard Q model based on stock market valuation is no \nlonger appropriate. Instead, we use the fundamental Q approach \nproposed by Abel and Blanchard (1986) and Gilchrist and Himmelberg \n(1995) and extend it to the case of several capital inputs. The results show \nthat the standard convex costs model fits very well equipment and but \nnot structures. We find evidence for non-convexities in the case of \nstructures.