Knowledge that Transforms

In this paper decision systems are structured so that topological concepts can be applied to formulate and help solve existence problems. Existence of stationary states and orbits is established. The analysis is then applied to programs, a special class of decision systems in which the decision operator is a mathematical program. The theory is extended to of many decision makers with rolling schedules of future actions. RECURSIVE DECISION SYSTEMS (RDS's) are dynamic systems based on discrete time that represent the positive behavior of decision makers. They have been put to three basic uses, (1) to describe the behavior of various economic sectors, (2) to show how indirect policies can in some particular way improve the performance of the economic system under investigation, and (3) to formulate and analyze a variety of dynamic economic theories. In this paper we define RDS's so that topological concepts and theorems can be used to study existence questions. Existence theorems are then given for stationary states and compact orbit sets. Special attention is given to the class of RDS's called programs (RP) of which various recursive program- ming models are special cases. The paper concludes with some brief comments on the assumptions used in the analysis. Before proceeding to the formal definitions, we briefly review in a nontechnical manner the basic concepts underlying RDS's and their use in economic research. RDS's as defined here are mathematical of socioeconomic processes having two basic components: (1) a decision operator that describes the manner in which final decisions or actions are derived from a given amount of information about the decision maker's environment ;2 and (2) afeedback operator that describes how decisions once acted on, or once scheduled for the future, interact with the decision maker's environment to produce new information upon which succeeding plans can be based.3 A given decision operator may represent the decision process not only of a single decision maker, but also of a group of decision makers who make their decisions independently-or collusively-during the same time period. Further- more, the decision at a given time may represent not only an immediate choice,

[All over the world economists are busy evaluating major road proposals and other transport projects. But this work is largely confined to rural areas because the methods used are inappropriate for evaluating big transport schemes in towns, where traffic congestion is a dominating consideration. This paper discusses congestion as an economic problem of demand and supply, expressed as simple functions of the cost of travel, in time and money, to the road user. Road expansion in congested cities often seems to achieve nothing but more congestion. This paper demonstrates how this arises as a process of market equilibrium, and how one can assess the benefits of the road expansion in this situation. The paper then considers how the evaluation of road schemes would be affected if direct road pricing were introduced into cities as a means of controlling congestion.]

A. L. Nagar, Y. P. Gupta, The Moment Matrix of the Two-Stage Least-Squares Estimator of Coefficients in Different Equations of a Complete System of Simultaneous Equations, Econometrica, Vol. 38, No. 1 (Jan., 1970), pp. 39-49

[Two stage least squares methods are used to estimate a postwar quarterly model of U.S. labor demand, supply, and wage adjustment. Analytical techniques are used to derive the long-run equilibrium properties of the estimated model. Short run properties are obtained by approximating the model in the form of two simultaneous difference equations. Simulation methods show the response of the model to an increase in the size of the armed forces.]

This article shows how to transform residuals from regression on an arbitrary set of k regressors to a set of values having the same joint distribution as the residuals from regression on a different set L of k regressors. Let d′ denote the value of the statistic <tex-math>$\Σ (z_t-z_t-1)^2/\Σ z_t^2$</tex-math> calculated from these values. It is shown that for a suitable choice of L the distribution of d′ is the same as that of <tex-math>d_U</tex-math>, the significance values of which are tabulated in [1].

[This paper begins by formulating a finite horizon linear programming model for economic development. The formulation allows for heterogeneous capital goods and for nonnegativity constraints upon investment in each sector. It is then proved that a certain set of conditions are sufficient to ensure that an optimal solution to this T period, finite horizon plan will also coincide with an optimal solution during the first T periods of an infinite horizon plan. Among the restrictive conditions imposed to prove this sufficiency theorem are the following: gradualist consumption paths, no primary factors that cannot themselves be produced within the economy, a Leontief technology, and a characterization of the optimal finite horizon solution as one in which the terminal investment and output levels are positive. An illustrative numerical example is provided.]

[This paper is concerned with the estimation of an econometric model for the Israeli economy as it existed through 1965. The model is disaggregated to seven sectors and contains substantial detail for import and export equations. Multiplier analysis suggests that the economy is stable for unemployment rates around eight percent but is unstable at full employment unless discretionary fiscal and monetary policies are applied. A new version of the IS-LM curve is developed to explain this result. The model is used to "forecast" the recession of 1966 and it is determined that the ex post record is more successful than official government predictions issued at that time.]

[A value share is defined as the ratio of the expenditure of the ith commodity to total expenditure. Some value shares go up and others go down in successive periods, and in this article the problem is raised whether one can define transitions from the ith share to the jth in an attractive way. The procedure is applied to Dutch data in the period 1921-1963.]

Computes a GLS matrix weighted estimator for a panel data set. meangroup.src does a similar estimator, but uses simple weighted average rather than a matrix-weighted average. Swamy(1970), Efficient Inference in a Random Coefficient Regression Model, Econometrica, vol 38, 311-323. (This abstract was borrowed from another version of this item.)