In an earlier paper,"Granger-causality and Policy Effectiveness," Economica [1984], I showed that for a policy instrument x to Granger-cause some target variable y is not necessary for x to be useful in controlling y. (The argument that it is not sufficient was already familiar, e.g. from the...

The note mines an unsuspected lode in the Sargent-Wallace "Unpleasant Monetarist Arithmetic" deposit. While that model is shown to be incapable of generating hyperinflations as a result of large monetized public sector deficits, it can generate hyperdeflations or perhaps more accurately, the...

The paper presents a general solution method for rational expectations models that can be represented by systems of. deterministic first order linear differential equations with constant coefficients. It is the continuous time adaptation of the method of Blanchard and Kahn. To obtain a unique...

The paper surveys some recent developments in policy evaluation and design in continuous time linear rational expectations models. Much recent work in macroeconomics and open economy macroeconomics fits into this category. First the continuous time analogue is reviewed of the discrete time...

In this note the method of Hamiltonian dynamics is used to characterize the time-consistent solution to the optimal control problem in a deterministic continuous time rational expectations model. A linear quadratic example based on the work of Miller and Salmon is used for simplicity. To derive...

The distinctiof between predetermined and non-predetermined variables is a crucial one in rational expectations models. I consider and reject two definitions, one proposed by Blanchard and Kahn and one by Chow. Both definitions lead to possible misc1assifications. Instead I propose the following...

The paper investigates the robustness of the proposition that in stochastic models contingent or feddback rules dominate fiped or openloop rules. Four arguments in favour of fixed rules are considere`. 1) The presence of an incompetent op malevolent policy maker. 2) A trade-off between...

The paper reviews recent developments in macroeconomic theory and their implications for econometric modelling and for policy design. The following issues are addressed. 1) The theoretical and practical problems of modelling sequence economies. 2) Problems of evaluating the role of money given...

The paper analyses a class of two-point boundary value problem for systems of linear differential equations with constant coefficients. The boundary conditions are expressed as linear restrictions on the state vector at an initial time and at a finite terminal time. This is applicable even if...

This paper aims to provide a stochastic, rational expectations extension of Tobin's "Money and Income; Post Hoc Ergo Proper Hoc?". It is well-known that money may Granger-cause real variables even though the joint density function of the real variables is invariant under changes in the...