Aid and Income: Another Time-series Perspective
复现了NDHKM（2012）的研究，发现其模型因变量对数变换导致大量观测值被非随机删除，且协整回归不适合估计援助对收入的因果效应。基于面板VAR模型，本文发现援助对收入有正向且统计显著的长期影响。
This study provides a replication of the empirical results reported by Nowak-Lehmann, Dreher, Herzer, Klasen, and Martínez-Zarzoso (2012) (henceforth NDHKM). We uncover that NDHKM relied on a regression model which included a log transformation of variables that are not strictly positive. This led to nonrandom omission of a large proportion of observations. Furthermore, we show that NDHKM’s use of co-integrated regressions is not a suitable empirical strategy for estimating the causal effect of aid on income. Evidence from a Panel VAR model estimated on the dataset of NDHKM, suggests a positive and statistically significant long-run effect of aid on income.