The impact of regulation on productivity growth: An application to the transmission sector of the interstate natural gas industry

We estimate a regulated cost function to examine the contributions of technical change, scale economies, and regulatory bias to productivity growth in an eleven-year, twenty-firm panel of interstate natural gas pipeline companies. We derive the unregulated cost function from the regulated cost function to produce estimates of movements in the unconstrained production technology. We find that the regulation constraint is binding in most years and that scale economies explain 38 percent more growth in the unconstrained production space than they do in the regulation-constrained production space.