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Underidentification test (Kleibergen-Paap rk LM statistic): 6.563
Chi-sq(1) P-val = 0.0104
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Weak identification test (Cragg-Donald Wald F statistic): 26.613
(Kleibergen-Paap rk Wald F statistic): 4.443
Stock-Yogo weak ID test critical values: 10% maximal IV size 16.38
15% maximal IV size 8.96
20% maximal IV size 6.66
25% maximal IV size 5.53
Source: Stock-Yogo (2005). Reproduced by permission.
NB: Critical values are for Cragg-Donald F statistic and i.i.d. errors.
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Hansen J statistic (overidentification test of all instruments): 0.000
(equation exactly identified)
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Instrumented: z_x
Included instruments: z_z z_z2 z_z3 z_z4 _Itime_2013 _Itime_2014 _Itime_2015
_Itime_2016 _Itime_2017 _Itime_2018 _Itime_2019
Excluded instruments: z_x_1
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以上是我回归分析的结果,不太清楚是否通过弱工具变量检验,查阅了好多帖子,有说Cragg-Donald Wald F statistic越大越好,越能说明不存在弱工具问题,也有说这个值不能太大。。。孩子太无助了,求助好心人解答。
另外,在陈强老师的书中是这么写的:“上表弱工具变量检验的Cragg-Donald Wald F 统计量显示,对于名义显著性水平为5%的检验,其真实显著性水平不会超过15%。”这个表中的Cragg-Donald Wald F值=14.906,位于10%maximal IV size和15%maximal IV size之间,这个例子的多个弱工具检验结果都是拒绝弱工具变量的。
那我的Cragg-Donald Wald F值=26.613,到底说明了啥呢?
另外,Stock-Yogo weak ID test critical values 到底怎么看,意味着什么呢?