In this paper we explore the absentminded driver problem using two different scenarios. In the first scenario we assume that the driver is capable of reasoning about his degree of absentmindedness before he hits the highway. This leads to a Savage-style model where the states are mutually exclusive and the act-state independence is in place. In the second we employ centred possibilities, by modelling the states (i.e. the events about which the driver is uncertain) as the possible final destinations indexed by a time period. The optimal probability we find for continuing at an exit is different from almost all papers in the literature. In this scenario, act-state independence is still violated, but states are mutually exclusive and the driver arrives at his optimal choice probability via Bayesian updating. We show that our solution is the only one guaranteeing immunity from sure loss via a Dutch strategy, and that – despite initial appearances – it is time consistent. This raises important implications for the rationality of commitment in such scenarios.

We give a dynamic extension result of the (static) notion of a deviation measure. We also study distribution-invariant deviation measures and show that the only dynamic deviation measure which is law invariant and recursive is the variance.

In a canonical monetary policy model in which the central bank learns about underlying fundamentals by estimating the parameters of a Phillips curve, we show that the bank’s loss function is asymmetric such that parameter overestimates may be more or less costly than underestimates, creating a precautionary motive in estimation. This motive suggests the use of a more efficient variance-adjusted least-squares estimator for learning about fundamentals. Informed by this “precautionary learning” the central bank sets low inflation targets, and the economy can settle near a Ramsey equilibrium.

This paper investigates the desirability of constitutional constraints on capital taxation in an environment without government debt and where benevolent governments have limited commitment. In our setup, governments can choose proportional capital and labor income taxes subject to the constitutional constraint but cannot commit to an actual path of taxes. First, we explore a form of constitutional constraint: a constant cap on capital tax rates. In our quantitative exercise, we show that a three percent cap on capital taxes provides the highest welfare at the worst sustainable equilibrium. However, such a cap decreases welfare at the best sustainable equilibrium (both because it constrains feasibility and because it tightens the incentive compatibility constraint). Second, we identify a form of constitutional constraint that can improve all sustainable equilibria. That constraint features a cap on capital taxes that increases with the level of capital.

A key result in macroeconomics is the “time inconsistency of short-run optimal plans.” It is argued that inflationary bias results if central bankers do not precommit to a monetary policy rule. The macro literature, however, does not address the way in which board members arrive at the “optimal choice of inflation rate.” That is a matter of a micro subfield called social choice. If we consider that on any board, members have different priors about the states of nature for the economy, but they all receive the same signal before deciding, then they will have different posterior probabilities for the states, even if they have many data, if one state has a low probability of occurring, such as an unlikely catastrophic-risk event. Thus, it is not clear what the optimal plan is. Therefore, discretion rather than rules may be the optimal plan in social choice settings.

We construct a theory of forward guidance in economic policy making in order to provide a framework for explaining the role and strategic advantages of including forward guidance as an explicit part of policy design. We do this by setting up a general policy problem in which forward guidance plays a role, and then examine the consequences for performance when that guidance is withdrawn. We show that forward guidance provides enhanced controllability and stabilizability—especially where such properties may not otherwise be available. As a by-product, we find that forward guidance limits the scope and incentives for time-inconsistent behavior in an economy whose policy goals are ultimately reachable. It also adds to the credibility of a set of policies.

Time inconsistency is an essential feature of many policy problems. This paper presents and compares three methods for computing Markov-perfect optimal policies in stochastic nonlinear business cycle models. The methods considered include value function iteration, generalized Euler equations, and parameterized shadow prices. In the context of a business cycle model in which a fiscal authority chooses government spending and income taxation optimally, although lacking the ability to commit, we show that the solutions obtained using value function iteration and generalized Euler equations are somewhat more accurate than that obtained using parameterized shadow prices. Among these three methods, we show that value function iteration can be applied easily, even to environments that include a risk-sensitive fiscal authority and/or inequality constraints on government spending. We show that the risk-sensitive fiscal authority lowers government spending and income taxation, reducing the disincentive to accumulate wealth that households face.

Consider the problem of a benevolent government that needs to finance the provision of a public good with distortionary taxes and cannot commit to policies beyond the current period. In such a case, public expenditure is inefficiently low. If the government further loses the ability to set tax rates before production in the period takes place, then it will not internalize how its policy choices distort current factor markets. Thus, to counterbalance the costs of future distortions, it increases public good provision. For a calibrated economy, removing within-period commitment implies a welfare gain worth half a percent of yearly consumption. A similar gain can be obtained if instead, capital depreciation is allowed to be fully deducted from taxable income.

We implement optimal economic outcomes at the lowest social cost by combining reputation and contracting mechanisms to overcome the time-inconsistency problem of monetary policy associated with an inflation bias. We characterize the conditions under which the reputation force alone induces a central bank to behave in a socially optimal way. When these conditions fail, an incentive contract is invoked, whose cost is significantly reduced by the presence of the reputation force. The contract poses a penalty threat that is a concave function of wage growth, which in equilibrium is tied to expected rather than realized inflation, with a global maximum that provides the least upper bound on all threatened penalties. This bound can be used as a uniform penalty threat to achieve optimal economic outcomes and still, for moderate to large shocks, its magnitude can be much smaller than the size of the transfers required by the standard contracts that are linear functions of realized inflation rates. Further, under both the concave and the uniform penalty threats, the central bank will behave in the socially optimal way and no transfer is materialized in equilibrium. Thus our hybrid mechanism solves the time-inconsistency problem while leaving the central bank with complete discretion to respond to new circumstances, without any reputation cost or penalty threatened by the contract actually invoked along the equilibrium path.

This paper develops a dynamic model of seigniorage in which economies' equilibrium paths reflect the ongoing strategic interaction between an optimizing government and a rational public. The model extends existing positive models of monetary policy and inflation by explicitly incorporating the intertemporal linkages among budget deficits, debt, and inflation. A central finding is that the public's rational responses to government policies may well create incentives for the government to reduce inflation and the public debt over time. A sufficiently myopic government may, however, provoke a rising equilibrium path of inflation and public debt.

This paper addresses the problem of multiple equilibria in a model of time-consistent monetary policy. It suggests that this problem originates in the assumption that agents have rational expectations and proposes several alternative restrictions on expectations that allow the monetary authority to build credibility for a disinflationary policy by demonstrating that it will stick to that policy even if it imposes short-run costs on the economy. Starting with these restrictions, the paper derives conditions that guarantee the uniqueness of the model's steady state; monetary policy in this unique steady state involves the constant deflation advocated by Milton Friedman.