Selection Effects with Heterogeneous Firms
研究了企业如何选择服务市场的方式，发现进入市场的选择效应很稳健，但进入后选择具体模式（如出口或投资）则取决于利润函数是否具有超模性，并给出了超模性的微观基础。
Abstract We characterize how firms select between alternative ways of serving a market. “First-order” selection effects, whether firms enter or not, are extremely robust. “Second-order” ones, how firms serve a market conditional on entry, are much less so: more efficient firms select the entry mode with lower market-access costs if firms’ maximum profits are supermodular in production and market-access costs, but not necessarily otherwise. We derive microfoundations for supermodularity in a range of canonical models. Notable exceptions include horizontal and vertical FDI with “subconvex” demands (i.e., less convex than CES), fixed costs that increase with productivity, and R&D with threshold effects.