“…Among the common empirical proxies for asset specificity are technical specifications like product complexity, qualitatively coded from survey data or quantitatively assigned by inspection, as a proxy for physical asset specificity (Masten, 1984;Bigelow, 2001); worker-specific knowledge, again coded from survey data, as a proxy for human asset specificity Teece, 1982a, 1982b;Masters and Miles, 2002); physical proximity of contracting firms, as a proxy for site specificity (Joskow, 1985(Joskow, , 1987(Joskow, , 1988b(Joskow, , 1990Spiller, 1985;González,-Diaz, Arruñada, and Fernández, 2000); and spatial and temporal proximity (Masten, Meehan, and Snyder, 1991;Pirrong, 1993;Hubbard, 1999). Other proxies, such as fixed costs or "capital intensity," have more obvious limitations and are rarely used.…”