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Full-Text Articles in Economics

Dynamic Panel Gmm With Near Unity, Peter C.B. Phillips Dec 2014

Dynamic Panel Gmm With Near Unity, Peter C.B. Phillips

Cowles Foundation Discussion Papers

Limit theory is developed for the dynamic panel GMM estimator in the presence of an autoregressive root near unity. In the unit root case, Anderson-Hsiao lagged variable instruments satisfy orthogonality conditions but are well-known to be irrelevant. For a fixed time series sample size (T) GMM is inconsistent and approaches a shifted Cauchy-distributed random variate as the cross section sample size n → ∞. But when T → ∞, either for fixed n or as n → ∞, GMM is √ T consistent and its limit distribution is a ratio of random variables that converges to twice a standard Cauchy …


Identifying Latent Structures In Panel Data, Liangjun Su, Zhentao Shi, Peter C.B. Phillips Dec 2014

Identifying Latent Structures In Panel Data, Liangjun Su, Zhentao Shi, Peter C.B. Phillips

Cowles Foundation Discussion Papers

This paper provides a novel mechanism for identifying and estimating latent group structures in panel data using penalized regression techniques. We focus on linear models where the slope parameters are heterogeneous across groups but homogenous within a group and the group membership is unknown. Two approaches are considered — penalized least squares (PLS) for models without endogenous regressors, and penalized GMM (PGMM) for models with endogeneity. In both cases we develop a new variant of Lasso called classifier-Lasso (C-Lasso) that serves to shrink individual coefficients to the unknown group-specific coefficients. C-Lasso achieves simultaneous classification and consistent estimation in a single …


True Limit Distributions Of The Anderson-Hsiao Iv Estimators In Panel Autoregression, Peter C.B. Phillips, Chirok Han Dec 2014

True Limit Distributions Of The Anderson-Hsiao Iv Estimators In Panel Autoregression, Peter C.B. Phillips, Chirok Han

Cowles Foundation Discussion Papers

This note derives the correct limit distributions of the Anderson Hsiao (1981) levels and differences instrumental variable estimators, provides comparisons showing that the levels IV estimator has uniformly smaller variance asymptotically as the cross section ( n ) and time series ( T ) sample sizes tend to infinity, and compares these results with those of the first difference least squares (FDLS) estimator.


Initial-Condition Free Estimation Of Fixed Effects Dynamic Panel Data Models, Zhenlin Yang Sep 2014

Initial-Condition Free Estimation Of Fixed Effects Dynamic Panel Data Models, Zhenlin Yang

Research Collection School Of Economics

It is well known that (quasi) MLE of dynamic panel data (DPD) models with short panels depends on the assumptions on the initial values; ignoring them or a wrong treatment of them will result in inconsistency or serious bias. This paper introduces a initial-condition free method for estimating the fixed-effects DPD models, through as simple modification of the quasi-score. An outer-product-of-gradients (OPG) method is also proposed for robust inference. The MLE of Hsiao, Pesaran and Tahmiscioglu (2002, Journal of Econometrics), where the initial observations are modeled, is extended to quasi MLE and an OPG method is proposed for robust inference. …


Identifying Latent Structures In Panel Data, Liangjun Su, Zhentao Shi, Peter C. B. Phillips Aug 2014

Identifying Latent Structures In Panel Data, Liangjun Su, Zhentao Shi, Peter C. B. Phillips

Research Collection School Of Economics

This paper provides a novel mechanism for identifying and estimating latent group structures in panel data using penalized regression techniques. We focus on linear models where the slope parameters are heterogeneous across groups but homogenous within a group and the group membership is unknown. Two approaches are considered — penalized least squares (PLS) for models without endogenous regressors, and penalized GMM (PGMM) for models with endogeneity. In both cases we develop a new variant of Lasso called classifier-Lasso (C-Lasso) that serves to shrink individual coefficients to the unknown group-specific coefficients. C-Lasso achieves simultaneous classification and consistent estimation in a single …