[Testing for Common Features]: Comment
指出Engle-Kozicki的共同特征方法在国际商业周期应用中存在反直觉且不可取的隐含结论，这些结论需逐案例推导，建议应用时关注这些可能性。
I show that the Engle-Kozicki formulation of common features--applied to international business cycles--has some surprising, counterintuitive, and, I argue, undesirable implications. Such implications can be derived only on a case-by-case basis, however, and are necessarily specific to each application. Therefore, some attention to those possibilities might usefully accompany each application of the general common-features principle.