Forecasting Vector ARMA Processes With Systematically Missing Observations

The following two predictors are compared for time series with systematically missing observations: (a) A time series model is fitted to the full series X_t , and forecasts are based on this model, (b) A time series model is fitted to the series with systematically missing observations Y _τ, and forecasts are based on the resulting model. If the data generation processes are known vector autoregressive moving average (ARMA) processes, the first predictor is at least as efficient as the second one in a mean squared error sense. Conditions are given for the two predictors to be identical. If only the ARMA orders of the generation processes are known and the coefficients are estimated, or if the process orders and coefficients are estimated, the first predictor is again, in general, superior. There are, however, exceptions in which the second predictor, using seemingly less information, may be better. These results are discussed, using both asymptotic theory and small sample simulations. Some economic time series are used as illustrative examples.     

Comment

We propose a sequential test for predictive ability for recursively assessing whether some economic variables have explanatory content for another variable. In the forecasting literature it is common to assess predictive ability by using “one-shot” tests at each estimation period. We show that this practice leads to size distortions, selects overfitted models and provides spurious evidence of in-sample predictive ability, and may lower the forecast accuracy of the model selected by the test. The usefulness of the proposed test is shown in well-known empirical applications to the real-time predictive content of money for output and the selection between linear and nonlinear models.     

Some Observations,a Suggestion,and Some Comments on the Conway-Roberts Article

This article provides new tools for the evaluation of dynamic stochastic general equilibrium (DSGE) models and applies them to a large-scale new Keynesian model. We approximate the DSGE model by a vector autoregression, and then systematically relax the implied cross-equation restrictions and document how the model fit changes. We also compare the DSGE model's impulse responses to structural shocks with those obtained after relaxing its restrictions. We find that the degree of misspecification in this large-scale DSGE model is no longer so large as to prevent its use in day-to-day policy analysis, yet is not small enough to be ignored.     

STAR非线性平稳性检验中误设定的伪检验研究

本文通过理论分析和蒙特卡洛仿真模拟,研究平稳性检验中选用的统计量与数据生成过程不一致时,非线性ESTAR、LSTAR与线性DF检验法能否得出正确的结论.研究表明,二阶LSTAR与ESTAR模型可用相同的检验方法,但前者的非线性特征更强.当数据生成过程为线性AR,或非线性ESTAR、二阶LSTAR模型时,使用DF或ESTAR检验法可得出大致正确的结论,但LSTAR检验法完全失败.数据生成过程的非线性特征越强,ESTAR较DF检验方法的功效增益越高;线性特征越强,DF的功效增益越高.当转移函数F(θ,c,zt)中θ较大导致一阶泰勒近似误差较大或c非0时,标准ESTAR与LSTAR非线性检验法失去应用条件.θ较大或c偏离0较远时,数据生成过程中线性成分增强,用线性DF检验可获得更好的检验结果.     

Penalized Maximum Likelihood Principle for Choosing Ridge Parameter

We consider the problem of choosing the ridge parameter. Two penalized maximum likelihood (PML) criteria based on a distribution-free and a data-dependent penalty function are proposed. These PML criteria can be considered as “continuous” versions of AIC. A systematic simulation is conducted to compare the suggested criteria to several existing methods. The simulation results strongly support the use of our method. The method is also applied to two real data sets.     

Evaluating the Effective Degrees of Freedom of the Delete-a-Group Jackknife

The delete-a-group jackknife is sometimes used when estimating the variances of statistics based on a large sample. We investigate heavily poststratified estimators for a population mean and a simple regression coefficient, where both full-sample and domain estimates are of interest. The delete-a-group (DAG) jackknife employing 30, 60, and 100 replicates is found to be highly unstable, even for large sample sizes. The empirical degrees of freedom of these DAG jackknives are usually much less than their nominal degrees of freedom. This analysis calls into question whether coverage intervals derived from replication-based variance estimators can be trusted for highly calibrated estimates.     

Exponentiated power Lindley power series class of distributions: Theory and applications

ABSTRACT

We introduce a new four-parameter generalization of the exponentiated power Lindley (EPL) distribution, called the exponentiated power Lindley power series (EPLPS) distribution. The new distribution arises on a latent complementary risks scenario, in which the lifetime associated with a particular risk is not observable; rather, we observe only the minimum lifetime value among all risks. The distribution exhibits a variety of bathtub-shaped hazard rate functions. It contains as particular cases several lifetime distributions. Various properties of the distribution are investigated including closed-form expressions for the density function, cumulative distribution function, survival function, hazard rate function, the rth raw moment, and also the moments of order statistics. Expressions for the Rényi and Shannon entropies are also given. Moreover, we discuss maximum likelihood estimation and provide formulas for the elements of the Fisher information matrix. Finally, two data applications are given showing flexibility and potentiality of the EPLPS distribution.     

High-order extensions of the Double Chain Markov Model

The Double Chain Markov Model is a fully Markovian model for the representation of time-series in random environments. In this article, we show that it can handle transitions of high-order between both a set of observations and a set of hidden states. In order to reduce the number of parameters, each transition matrix can be replaced by a Mixture Transition Distribution model. We provide a complete derivation of the algorithms needed to compute the model. Three applications, the analysis of a sequence of DNA, the song of the wood pewee, and the behavior of young monkeys show that this model is of great interest for the representation of data that can be decomposed into a finite set of patterns.     

IFLA Library Reference Model,RDA, and Serials in a Nutshell

Abstract

IFLA Library Reference Model (IFLA LRM) represents the consolidation of Functional Requirements for Bibliographic Records (FRBR) and the two other conceptual models of the Functional Requirements (FR) family, the Functional Requirements for Authority Data (FRAD) and the Functional Requirements for Subject Authority Data (FRSAD). IFLA LRM includes a specific section (5.8) devoted to serials. The RDA Steering Committee adopted IFLA LRM as the conceptual model for the development of RDA in November 2016. The 3R (RDA Toolkit Restructure and Redesign) Project’s purpose is partly to make RDA compatible with the IFLA LRM. A beta version of the English-language content of the RDA Toolkit, which incorporates the IFLA LRM, was released in June 2018. This column explores, in lay terms, serials in relation to the IFLA LRM and the RDA Toolkit Restructure and Redesign (3R) Project. The beta version of the restructured and redesigned RDA Toolkit introduces several new concepts relating to serials.     

Book reviews

Donald J. Koosis: Statistics. A Self-Teaching Guide, Fourth Edition. Wiley 1997, ISBN 0-471-14688-9

Christopher C. Heyde: Quasi-Likelihood and Its Applications, Springer Series in Statistics, 1997, pp. 235, [ISBN 0-387-98225-61

Jeffrey S. Simonoff: Smoothing Methods in Statistics, Springer Series in Statistics, 1996, pp. 338

Andr´e I. Khuri, Thomas Mathew and Birmal K. Sinha: Statistical Tests for Mixed Linear Models, Wiley Series in Probability and Statistics, 1998, pp. 352, PSBN 0-471-1 5653-11

Ronald Christensen: Log-Linear Models and Logistic Regression, Springer Texts in Statistics, 1997, pp. 483, [ISBN 0-387-98247-71

E. L. Lehmann: Testing Statistical Hypotheses, Springer Texts in Statistics, 1997, pp. 600, [ISBN 0-387-94919-41

S. R. Searle, G. Casella and Ch. E. McCulloch: Variance Components, Wiley and Sons, 1992, pp. 496, [ISBN 0-471-62162-51

B. J. T. Morgan: Analysis of Quantal Response Data, Chapman & Hall, 1992, pp. 51 1

Carl D. Huberty: Applied Discriminant Analysis, Wiley and Sons, 1994, pp. 490

C. R. Rao and H. Toutenburg: Linear Models. Least Squares and Alternatives, Springer Series in Statistics, 1995, 188 pp., [ISBN 0-387-94562-81