“…The common practice of approximating the initial capital stock in micro-level studies relies on proxy variables. In the case of physical capital, the most frequent approach is to initialize the PIM using the book value of fixed tangible assets (Olley and Pakes, 1996;Pavcnik, 2002;Levinsohn and Petrin, 2003;Foster et al, 2016); other authors propose to use a production-related variable, such as labor demand, intermediate materials, energy consumption, or purchased services, as the proxy variable for the initial capital stock (Martin, 2002;Gilhooly, 2009). While some proxies, such as the book value, are used more often than others, there is no empirical evidence to conclude that any one of them is superior to the others.…”