A simple data-dependent filtering method is proposed before applying the Bai–Ng method to estimate the number of common factors in the conventional approximate factor model. The asymptotic justification is provided and the finite-sample performance is examined.

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...

In the standard generalized method of moments estimation of dynamic panel data models, the constant term is usually omitted from instrument sets. As a result, adding a constant to the dependent variable affects the estimates for models without full period dummies. Omitting the constant term from...

In this paper we propose a simple L1-GMM consistent estimator for linear structural equations models when some instruments are invalid. A simple method to detect invalid instruments is also proposed.

By treating one nuisance parameter as two distinct parameters and using some moment conditions twice, we provide an explanation to a paradox in the inverse probability weighting estimation of the average treatment effect on the treated.

Utilizing recursive mean adjustment (RMA) we provide two unit root tests: the covariate RMA unit root test and the panel feasible generalized RMA unit root test. The proposed panel unit root tests are precise and powerful, especially when T > N.