ON THE FIRST–ORDER EFFICIENCY AND ASYMPTOTIC NORMALITY OF MAXIMUM LIKELIHOOD ESTIMATORS OBTAINED FROM DEPENDENT OBSERVATIONS

Abstract. In this paper we study the first–order efficiency and asymptotic normality of the maximum likelihood estimator obtained from dependent observations. Our conditions are weaker than usual, in that we do not require convergences in probability to be uniform or third–order derivatives to exist.
The paper builds on Witting and Nolle's result concerning the asymptotic normality of the maximum likelihood estimator obtained from independent and identically distributed observations, and on a martingale theorem by McLeish.     

On exact D-optimal designs with 2 two-level factors and n autocorrelated observations

In this paper we consider the exact D-optimal designs for estimation of the unknown parameters in the two factors, each at only two-level, main effects model with autocorrelated errors. The vector of the n random errors in the observed responses is assumed to follow a first-order autoregressive model (AR(1)). The exact D-optimal designs seek the optimal combinations of the design levels as well as the optimal run orders, so that the determinant of the information matrix of BLUEs for the unknown parameters is maximized. Bora-Senta and Moyssiadis (1999) gave some conjectures about the exact D-optimal designs based on their experience of several exhaustive searches. In this paper their conjectures are partially proved to be true.Received: January 2003 / Accepted: October 2003Partially supported by the National Science Council of Taiwan, R.O.C. under grant NSC 91-2115-M-008-013.Supported in part by the National Science Council of Taiwan, R.O.C. under grant NSC 89-2118-M-110-003.     

An application of data envelopment analysis to evaluate the efficiency level of the operational cost of Brazilian electricity distribution utilities

This paper shows efficiency indices for 60 Brazilian electricity distribution utilities. The efficiency scores are gauged by three DEA models. For both models, these quantities are evaluated under different contexts. One treats with respect to the regulator perspective. The others examine an alternative approach based on cluster analysis and restrictions on factor weights. It is worth pointing out that these developments can reduce the information asymmetry and improve the regulator's skill to compare the performance of the utilities, a fundamental in incentive regulation schemes.     

Assets,activities and income generation in rural Mexico: factoring in social and public capital⋆

In recent years, there has been increasing emphasis in the rural development literature on the multiple income‐generating activities undertaken by rural households and the importance of assets in determining the capacity to undertake these activities. Controlling for the endogeneity of activity choice and applying Lee's generalisation of Amemiya's two‐step estimator to a simultaneous equation model, household returns to assets from multiple activities are explored for the Mexico ejido sector. To incorporate the multiple variables representing social and public capital into the analysis, factor analysis is used. The results indicate that the asset position of the household has a significant effect on household participation in income‐generating activities and returns to those activities. Furthermore, the inclusion of measures of social and public capital into the analysis show that these assets play an important role in income‐generating activities and that the influence is dependent on the type of social and public capital as well as the particular activity.     

A two-state analysis of estate taxes and charitable bequests from the most generous decedents

This study uses Censored Quantile Regression (CQR) and probate records for the years 2000–2005 to analyze charitable bequests of the most generous decedents from two states, Virginia and Louisiana. We focus on the most generous decedents because they account for a large portion of total charitable bequests. The most generous decedents' charitable bequest tax price (i.e., one minus the marginal tax rate) elasticity is not significantly greater than one in both our full sample and the subsample of the decedents filing federal estate tax returns. Our finding suggests that allowing charitable bequests to be deductible is not a treasury efficient policy for the most generous decedents. We also find that the tax price and wealth effects for the most generous decedents are overestimated by the Tobit model that has been traditionally utilized by prior studies. Furthermore, filers' charitable bequests are predicted to decrease if the estate tax is repealed.     

The generalized value at risk admissible set: constraint consistency and portfolio outcomes

Generalized value at risk (GVaR) adds a conditional value at risk or censored mean lower bound to the standard value at risk and considers portfolio optimization problems in the presence of both constraints. For normal distributions the censored mean is synonymous with the statistical hazard function, but this is not true for fat-tailed distributions. The latter turn out to imply much tighter bounds for the admissible portfolio set and indeed for the logistic, an upper bound for the portfolio variance that yields a simple portfolio choice rule. The choice theory in GVaR is in general not consistent with classic Von Neumann–Morgenstern utility functions for money. A re-specification is suggested to make it so that gives a clearer picture of the economic role of the respective constraints. This can be used analytically to explore the choice of portfolio hedges.     

OPTIMAL CONSUMPTION AND PORTFOLIO DECISIONS WITH PARTIALLY OBSERVED REAL PRICES

We consider optimal consumption and portfolio investment problems of an investor who is interested in maximizing his utilities from consumption and terminal wealth subject to a random inflation in the consumption basket price over time. We consider two cases: (i) when the investor observes the basket price and (ii) when he receives only noisy observations on the basket price. We derive the optimal policies and show that a modified Mutual Fund Theorem consisting of three funds holds in both cases. The compositions of the funds in the two cases are the same, but in general the investor's allocations of his wealth into these funds will differ. However, in the particular case when the investor has constant relative risk-aversion (CRRA) utility, his optimal investment allocations into these funds are also the same in both cases.     

Multi‐state Stochastic Processes: A Statistical Flowgraph Perspective

Two‐state models (working/failed or alive/dead) are widely used in reliability and survival analysis. In contrast, multi‐state stochastic processes provide a richer framework for modeling and analyzing the progression of a process from an initial to a terminal state, allowing incorporation of more details of the process mechanism. We review multi‐state models, focusing on time‐homogeneous semi‐Markov processes (SMPs), and then describe the statistical flowgraph framework, which comprises analysis methods and algorithms for computing quantities of interest such as the distribution of first passage times to a terminal state. These algorithms algebraically combine integral transforms of the waiting time distributions in each state and invert them to get the required results. The estimated transforms may be based on parametric distributions or on empirical distributions of sample transition data, which may be censored. The methods are illustrated with several applications.     

The demand for alcoholic beverages in Spain

The objective of this study is to analyze the main determinants of alcoholic beverages consumption at home. Data comes from the latest Spanish Household National Survey, which provides information on expenditure and quantities of different food products by household. Because households are interviewed only 1 week, a large number of zeros have been recorded. Among the existing censured demand models (the double hurdle (DH) model; the purchase‐infrequency model; and the Tobit purchase‐infrequency model, among others) and after carrying out model selection tests, the DH model has been finally estimated. All expenditure elasticities are positive, corresponding the highest value to spirits. Own price elasticities are negative and also in this case the spirits exhibit the highest value. Socio‐economic variables also play an important role in explaining consumer purchase and consumption decisions.