One part of the literature on endogenous growth concerns models where public infrastructure affects the private production process. An unsolved puzzle in this literature concerns observed public investment-to-output ratios for developed economies, which tend to fall short of theoretical model-based optimal ratios. We reexamine the optimal choice of public investment in a more general framework. This setting allows for long-lasting capital stocks, a lower depreciation rate for public capital than for private capital, an elasticity of intertemporal substitution that differs from unity, and the need to finance a nontrivial share of public services in output. Given other fundamentals in the economy, we show that the optimal public investment-to-output ratio is smaller for low-growth economies, for economies populated by consumers with low preferences for substituting consumption intertemporally, and when public capital is durable. For a calibrated economy, we show that a combination of these factors solves the public investment puzzle.

It is customary for the Interviewer to begin with an introduction describing the circumstances of the interview and providing an overview of the nature and importance of the work of the interviewee. However, in this case, as Editor of this journal, I feel it would be presumptuous of me to provide my own overview and evaluation of the work of this great man, Paul Samuelson. The scope of his contributions has been so vast (averaging almost one technical paper per month for over 50 years) that it could be particularly difficult to identify those areas of modern economic theory to which he has not made seminal contributions.Perhaps those rare exceptions might include game theoretic and topological models and maybe the recent literatures on complex unstable nonlinear dynamics, sunspots, and incomplete markets. But I would not be surprised, if he were to correct those speculations as misperceptions, if I were to ask. In addition to his over 550 published papers, his books are legendary. He once said: “Let those who will—write the nation's laws–if I can write its textbooks.”

Instead of attempting to provide my own overview, I am limiting this introduction to the following direct (slightly edited) quotation of a few paragraphs from the Web site, The History of Economic Thought, which is maintained online by the New School University in New YorkThe current URL of that Web site is http://cepa.newschool.edu/het/home.htm.: Perhaps more than anyone else, Paul A. Samuelson has personified mainstream economics in the second half of the twentieth century. The writer of the most successful principles textbook ever (1948), Paul Samuelson has been not unjustly considered the incarnation of the economics ‘establishment’—and as a result, has been both lauded and vilified for virtually everything right and wrong about it.Samuelson's most famous piece of work, Foundations of Economic Analysis (1947), is one of the grandest tomes that helped revive Neoclassical economics and launched the era of the mathematization of economics. Samuelson was one of the progenitors of the Paretian revival in microeconomics and the Neo-Keynesian Synthesis in macroeconomics during the post-war period.The wunderkind of the Harvard generation of 1930s, where he studied under Schumpeter and Leontief, Samuelson had a prodigious grasp of economic theory, which has since become legendary. An unconfirmed anecdote has it that at the end of Samuelson's dissertation defense, Schumpeter turned to Leontief and asked, ‘Well, Wassily, have we passed?’ Paul Samuelson moved on to M.I.T. where he built one of the century's most powerful economics departments around himself. He was soon joined by R.M. Solow, who was to become Samuelson's sometime co-writer and partner-in-crime.Samuelson's specific contributions to economics have been far too many to be listed here—being among the most prolific writers in economics. Samuelson's signature method of economic theory, illustrated in his Foundations (1947), seems to follow two rules which can also be said to characterize much of Neoclassical economics since then: With every economic problem, (1) reduce the number of variables and keep only a minimum set of simple economic relations; and (2) if possible, rewrite it as a constrained optimization problem.In microeconomics, he is responsible for the theory of revealed preference (1938, 1947). This and his related efforts on the question of utility measurement and integrability (1937, 1950) opened the way for future developments by Debreu, Georgescu-Roegen, and Uzawa. He also introduced the use of comparative statics and dynamics through his ‘correspondence principle’ (1947), which was applied fruitfully in his contributions to the dynamic stability of general equilibrium (1941, 1944). He also developed what are now called ‘Bergson-Samuelson social welfare functions’ (1947, 1950, 1956); and, no less famously, Samuelson is responsible for the harnessing of ‘public goods’ into Neoclassical theory (1954, 1955, 1958).Samuelson was also instrumental in establishing the modern theory of production. His Foundations (1947) are responsible for the envelope theorem and the full characterization of the cost function. He made important contributions to the theory of technical progress (1972). His work on the theory of capital is well known, if contentious. He demonstrated one of the first remarkable ‘Non-Substitution’ theorems (1951) and, in his famous paper with Solow (1953), initiated the analysis of dynamic Leontief systems. This work was reiterated in his famous 1958 volume on linear programming with Robert Dorfman and Robert Solow, wherein we also find a clear introduction to the ‘turnpike’ conjecture of linear von Neumann systems. Samuelson was also Joan Robinson's main adversary in the Cambridge Capital Controversy—introducing the ‘surrogate’ production function (1962), and then subsequently (and graciously) relenting (1966).In international trade theory, he is responsible for the Stolper–Samuelson Theorem and, independently of Lerner, the Factor Price Equalization theorem (1948, 1949, 1953), as well as (finally) resolving the age-old ‘transfer problem’ relating terms of trade and capital flows, as well as the Marxian transformation problem (1971), and other issues in Classical economics (1957, 1978).In macroeconomics, Samuelson's multiplier-accelerator macrodynamic model (1939) is justly famous, as is the Solow–Samuelson presentation of the Phillips Curve (1960) to the world. He is also famous for popularizing, along with Allais, the ‘overlapping generations’ model which has since found many applications in macroeconomics and monetary theory. In many ways, his work on speculative prices (1965) effectively anticipates the efficient markets hypothesis in finance theory. His work on diversification (1967) and the ‘lifetime portfolio’ (1969) is also well known.Paul Samuelson's many contributions to Neoclassical economic theory were recognized with a Nobel Memorial prize in 1970.

We use the longest span data that have ever been studied before (from 1870 to 2014) to investigate the relationship between the price of oil and the level of economic activity in the United States. In the context of a bivariate (identified) structural generalized autoregressive conditional heteroscedasticity (GARCH)-in-Mean VAR in real output growth and the change in the real price of oil, we find that uncertainty about oil prices has had a negative and significant effect on real output. We also find that the responses of real output growth to positive and negative shocks are not very informative of whether they are symmetric or asymmetric, and that accounting for oil price uncertainty tends to amplify the negative dynamic response of real output growth to unfavorable (positive) oil price shocks.

This paper evaluates the effectiveness of short-time work (STW) extensions—e.g., relaxing eligibility criteria or implementing new schemes—in OECD countries during the Great Recession. First, we find that the dampening effect of STW on the unemployment rate diminishes at higher take-up rates. Second, only countries with pre-existing STW schemes were able to fully exploit the benefits of STW. Third, the effects of STW were strongest when GDP growth was deeply negative at the beginning of the recession. In summary, our results indicate that STW is most effective when used as a fast-responding automatic stabilizer.

In the existing literature, panic-based bank runs are triggered by a commonly acknowledged and observed sunspot signal. There are only two equilibrium realizations resulting from the commonly observed sunspot signal: Everyone runs or no one runs. I consider a more general and more realistic situation in which consumers observe noisy private sunspot signals. If the noise in the signals is sufficiently small, there exists a proper correlated equilibrium for some demand deposit contracts. A full bank run, a partial bank run (in which some consumers panic whereas others do not), or no bank run occurs, depending on the realization of the sunspot signals. If the probabilities of runs are small, the optimal demand deposit contract tolerates full and partial bank runs.

Peter Diamond is one of the major contributors to economics during the last half century. His many contributions include research on growth, Social Security, public finance more generally, the economics of uncertainty, search theory, in particular, and economic dynamics, in general. This work has shaped the way we think about many economic problems, and the way in which we formalize them. Among his long list of honors and awards, he is a fellow of the Econometric Society, a Guggenheim Fellow, a Fellow of the American Academy of Arts and Sciences, a Member of the National Academy of Sciences, and a Nemmers Prize winner. The National Science Foundation has supported his work for the last 40 years. A recent check indicated 9 books and 132 published articles, and there are few signs of any slowdown.

We examine the nexus between land transfers and human capital formation. A sequence of land redistributions enables the beneficiaries to educate their children and thus to escape from poverty. A successful land reform allows the transition of a society from an agriculture-based state of poverty to a human capital–based developed economy. We find that a temporary state of inequality among the poor is unavoidable. Finally, we discuss the political economy of land reform, whether access to land markets should be allowed for beneficiaries of land reforms, and property rights issues.

This paper analyzes government spending multipliers in a two-country model of a monetary union with price stickiness and home bias in consumption where monetary policy is constrained by the zero lower bound (ZLB) on the nominal interest rate. Government spending multipliers under this constraint are computed and compared with fiscal multipliers in normal times, that is, where the central bank sets the nominal interest rate via a Taylor rule. The trade elasticity and the parameter measuring home bias in consumption play an important role in determining the size of the multiplier. The multipliers are not necessarily large under the ZLB constraint. However, compared with the fiscal multipliers when the central bank sets the nominal interest rate according to a Taylor rule, the multipliers under the ZLB are bigger. Moreover, the persistence parameter of the binding ZLB plays a crucial role.

Because they ignore the household-level and macroeconomic adjustments associated with longevity improvements, the actuarial projections of the Social Security Administration overestimate the Social Security crisis. Using a general-equilibrium model with heterogeneous households and incomplete markets, I show that with these adjustments accounted for, a significantly smaller decline in benefits is needed to balance the Social Security budget. Households respond by delaying retirement and Social Security benefit collection, by working more hours, and by also saving more. In general equilibrium, these effects lead to a natural expansion of Social Security's tax base and generate significant delayed retirement credits, which the actuarial estimates completely overlook.

Three important current areas of research in the field of international comparisons are the construction of price indexes at the basic heading level, price indexes at higher levels of aggregation, and the linking of comparisons across regions. We consider recent innovations in each of these areas. These innovations have largely arisen out of International Comparisons Program (ICP) 2005, and hence we discuss them in this context. We give particular emphasis to the construction of price indexes at the basic heading level, because we believe it is here that the biggest problems lie. For example, the apparently anomalous results obtained for China and India in ICP 2005 can be traced back to problems at the basic heading level. We also highlight some inconsistencies in current ICP methodology and some promising areas for future research that warrant closer scrutiny in the next round of ICP.

I demonstrate that the precise timing of financial markets and goods markets in a simple cash good/credit good model does not matter for the main results in the Ramsey literature on optimal fiscal and monetary policy. In Ramsey models based on Lucas and Stokey [Journal of Monetary Economics 12, 55–93 (1983)] and Chari, Christiano, and Kehoe [Journal of Money, Credit, and Banking 23, 519–539 (1991)], nominal money holdings are freely adjustable in response to shocks in the period in which they will be used to purchase consumption. In contrast, under Svensson [Journal of Political Economy 93, 919–944 (1985)] timing, nominal balances cannot be adjusted in the period they will be used. The broad finding is that benchmark Ramsey results are not very sensitive to this slight, ultimately ad hoc, modification. In particular, optimal inflation continues to display very high variability just as in the original models, although this can differ depending on exactly which exogenous processes are driving the economy. That the basic results in the Ramsey literature are not sensitive to the choice of cash/credit timing is reassuring as Ramsey analysis is applied to an ever-expanding set of model environments.

This paper provides estimates of the welfare cost of volatility attributable to monetary and fiscal policy shocks. It uses a continuous-time stochastic dynamic general equilibrium model based on a recursive utility function that disentangles risk aversion from intertemporal substitution. We find that monetary and fiscal policy shocks may lead to opposite welfare effects: negative for monetary growth shocks, but positive for government expenditure shocks. Furthermore, we find that welfare costs are sensitive to the parameter values chosen for risk aversion and intertemporal substitution, and we conclude that welfare costs are potentially much larger than that found by Lucas, forcing some modification of the policy conclusions associated with Lucas's pioneering work.

We generalize a money-in-the-utility function model to include interest-bearing deposits and use the model to estimate the welfare cost of inflation. In the model, the user cost of deposits is invariant to inflation in steady state. Currency and deposits are assumed to be weakly separable and the model is calibrated using index number methods. We find that the welfare cost of inflation is substantially lower in the model with interest-bearing deposits than in models where all monetary assets are assumed to be non-interest bearing. We also show that higher inflation can raise or lower the rate of convergence to steady state depending on the coefficient of relative risk aversion, but the effect is weak. We provide evidence for OECD countries suggesting that there could be a positive effect of inflation on user costs, which would lead to higher welfare cost estimates.

We present a method for using rational expectations in a linear-quadratic optimization framework. Following the approach put forward by Sims, we solve the model through a QZ decomposition, which is generally easier to implement than the more widely used Blanchard-Kahn method.

This paper argues that the marked reduction in the burden of parasitic and infectious diseases (PID) together with improved nutrition over the past two centuries in today's advanced countries has resulted in markedly improved physiological capital and cognitive skills and, consequently, in productivity advances. Using a unique annual dataset covering the period 1800–2011 for 21 OECD (Organisation for Economic Co-operation and Development) countries, it is found that health improvements can account for approximately a third of the productivity advances in the OECD countries since 1865, and that these improvements have been influential for enhancement in education, savings, innovations, life expectancy, and democracy.

Despite the important role that total factor productivity (TFP) has played in the growth literature, few attempts have been made to change the methodology to estimate it. This paper proposes a methodology based on a state-space model to estimate TFP and its determinants. With this methodology, it is possible to reduce the measurement of our ignorance. As a by-product, this estimate yields the capital share in output and the long-term growth rate. When applied to Chile, the estimation shows a capital share around 0.5 and long-term growth of TFP around 1%. Capital accumulation tends to explain the growth rate in the fast growth periods under the econometric estimation more than the traditional growth accounting methodology.

Vote-buying is widely used by parties in developing countries to influence the outcome of elections. We examine the impact of vote-buying on growth. We consider a model with a poverty trap where redistribution can promote growth. We show that vote-buying contributes to the persistence of poverty as taxed wealthy people buy votes from poor people. We then show that there exists a democratic constitution that breaks vote-buying and promotes growth. Such a constitution involves rotating agenda setting, a taxpayer-protection rule, and repeated voting. The latter rule makes vote-buying prohibitively costly.

This paper presents a quantitative analysis of the model developed by Galor and Moav [Galor, Oded and Omer Moav (2002) Natural selection and the origin of economic growth. Quarterly Journal of Economics 117(4), 1133–1191] in which agents vary genetically in their preference for quality and quantity of children. The simulation produces a pattern of income and population growth that resembles the period of Malthusian stagnation before the Industrial Revolution and the take-off into a modern growth era. We also investigate the stability of the modern growth era as an absorbing state of the model under the introduction of a strongly quantity-preferring genotype. We show that, given the absence of a scale effect of population in the model, the economy can regress to a Malthusian state under this change in the initial distribution of genotypes.

Even for the standard skill-biased technological change (SBTC) literature, the generic rise in the skill premium in the face of the relative increase in skilled workers since the 1980s seems a little puzzling. We develop a general equilibrium SBTC growth model that allows the dominance of either the price channel or the market-size channel mechanism through which network spillovers affect the technological-knowledge bias and, thus, the paths of intra-country wage inequality. The proposed mechanisms can accommodate facts not explained by the earlier literature.

We consider a model in which foreign and domestic traders buy the assets of both of two countries. Speculators in both countries use chartist or fundamentalist rules for forecasting the exchange rate. Demand for the assets of each country is determined by these forecasts. Perceptions of the fundamentals in each country are not necessarily the same. Rules are used with a certain probability depending on an agent's previous experience with them. The demands of the fundamentalist and chartist agents in the two countries determine the temporary equilibrium exchange rate at each point in time. This is unique under certain assumptions. With traders of both nationalities there is no need, as in other models, for an exogenous supply of foreign exchange. The model produces realistic features of the equilibrium exchange rate series. Periods in which the exchange rate tracks the fundamentals of one of the countries alternate with others in which bubbles appear.