Econometric models based on count data. Comparisons and applications of some estimators and tests

This paper deals with specification, estimation and tests of single equation reduced form type equations in which the dependent variable takes only non-negative integer values. Beginning with Poisson and compound Poisson models, which involve strong assumptions, a variety of possible stochastic models and their implications are discussed. A number of estimators and their properties are considered in the light of uncertainty about the data generation process. The paper also considers the role of tests in sequential revision of the model specification beginr ing with the Poisson case and provides a detailed application of the estimators and tests to a model of the number of doctor consultations.     

PLANT LOCATION ANALYSIS USING DISCRETE STOCHASTIC PROGRAMMING1*

A plant location model with two major aspects is outlined. First, discrete stochastic programming is used to handle variability in supplies and demands. Second, the cost structure of plants is modelled in more detail and with more realism than is usual. Results from applying the model to the Queensland cattle slaughtering industry demonstrate the inappropriateness of using traditional deterministic plant location models to analyse problems with major stochastic elements. Deterministic models yield plant locations, sizes, throughputs, commodity flows and implications which differ markedly from those generated by stochastic models in which plant sizes and locations are optimally matched to variable fat cattle supplies. In addition, the traditional deterministic long-run model overestimates the normative gains of industry rationalisation.     

The new independent trade unionism in Hungary

This article describes the development of political and economic reform in Hungary since 1956 and considers the recent emergence of independent trade unionism, particularly the new Democratic Union of Scientific Workers (TDDSZ). The author assesses the prospects for independent trade unionism in general as well as the reform of the official trade union movement (SZOT) in a rapidly changing political climate.     

The Underlying Return-Generating Factors for REIT Returns: An Application of Independent Component Analysis

Multifactor approaches to real estate returns have emphasized a macro-variables approach in preference to the latent factor approach originally used in arbitrage pricing theory. Use of high-frequency data, trading strategies and growing emphasis on the risks of extreme events makes the macrovariable procedure problematic. This article explores an alternative to the principal components analysis approach: independent components analysis (ICA). ICA seeks independence and maximizes a chosen risk parameter. We apply an ICA procedure based on a kurtosis maximization algorithm to real estate investment trust (REIT) data. The results show that ICA successfully captures kurtosis characteristics of REIT returns, offering possibilities for developing of risk management strategies that are sensitive to extreme events and tail distributions, augmenting traditional mean–variance approaches.     

On Efficient Estimation and Correct Inference in Models with Generated Regressors: a General Approach

Two approaches have been developed for deriving the properties of efficiency and consistency of standard errors of two step estimators of linear models containing current or lagged unobserved expectations of a single variable. One method is based on the derivatives of the likelihood function and information matrix, while the other uses the true covariance matrix of the disturbance vector when unknown parameters or variables are replaced by corresponding estimates. In this paper, the second approach is extended to cases where the structural equation is nonlinear and the model contains expectations of more than one variable or expectations of future variables. The properties of a frequently used estimator to deal with missing observations problems, a model involving a variance as an explanatory variable, and a recently developed estimator for autoregressive moving average models can be easily derived using the results of the paper. Methods for improving the efficiency of two step estimators are outlined.
JEL Classification Number: C13     

School Performance in Australia: Is There a Role for Quasi‐Markets?

Recent changes to the organisation of Australia's education system have raised the possibility of implementing wide‐ranging market reforms. In this article we discuss the scope for introducing reforms similar to the United Kingdom's ‘quasi‐market’ model. We discuss the role of school league tables in providing signals and incentives in a quasi‐market. Specifically, we compare a range of unadjusted and model‐based league tables of primary school performance in Queensland's public education system. These comparisons indicate that model‐based tables which account for socio‐economic status and student intake quality vary significantly from the unadjusted tables.