我可以使用lme4在面板数据上指定随机和固定效果模型吗？
我正在r中重做Wooldridge（2013，p.494-5）中的示例14.4。感谢this site和this blog post我已经在plm包中做到了，但是我很好奇我是否可以在lme4包中做到这一点？
这是我在plm包中所做的事情。对于任何有关如何使用lme4执行相同操作的指针，将不胜感激。首先，所需的软件包和数据加载，
# install.packages(c("wooldridge", "plm", "stargazer"), dependencies = TRUE)
library(wooldridge)
data(wagepan)
其次，我使用plm包估算了示例14.4（Wooldridge 2013）中估算的三个模型，
library(plm)
Pooled.ols <- plm(lwage ~ educ + black + hisp + exper+I(exper^2)+ married + union +
factor(year), data = wagepan, index=c("nr","year") , model="pooling")
random.effects <- plm(lwage ~ educ + black + hisp + exper + I(exper^2) + married + union +
factor(year), data = wagepan, index = c("nr","year") , model = "random")
fixed.effects <- plm(lwage ~ I(exper^2) + married + union + factor(year),
data = wagepan, index = c("nr","year"), model="within")
第三，我使用stargazer输出结果以模拟Wooldridge（2013）中的表14.2，
stargazer::stargazer(Pooled.ols,random.effects,fixed.effects, type="text",
column.labels=c("OLS (pooled)","Random Effects","Fixed Effects"),
dep.var.labels = c("log(wage)"), keep.stat=c("n"),
keep=c("edu","bla","his","exp","marr","union"), align = TRUE, digits = 4)
#> ======================================================
#> Dependent variable:
#> -----------------------------------------
#> log(wage)
#> OLS (pooled) Random Effects Fixed Effects
#> (1) (2) (3)
#> ------------------------------------------------------
#> educ 0.0913*** 0.0919***
#> (0.0052) (0.0107)
#>
#> black -0.1392*** -0.1394***
#> (0.0236) (0.0477)
#>
#> hisp 0.0160 0.0217
#> (0.0208) (0.0426)
#>
#> exper 0.0672*** 0.1058***
#> (0.0137) (0.0154)
#>
#> I(exper2) -0.0024*** -0.0047*** -0.0052***
#> (0.0008) (0.0007) (0.0007)
#>
#> married 0.1083*** 0.0640*** 0.0467**
#> (0.0157) (0.0168) (0.0183)
#>
#> union 0.1825*** 0.1061*** 0.0800***
#> (0.0172) (0.0179) (0.0193)
#>
#> ------------------------------------------------------
#> Observations 4,360 4,360 4,360
#> ======================================================
#> Note: *p<0.1; **p<0.05; ***p<0.01
在lme4中有同样简单的方法吗？我应该坚持plm吗？为什么/为什么不呢？
最佳答案
除了估计方法的差异外，似乎确实主要是一个问题
词汇和语法
# install.packages(c("wooldridge", "plm", "stargazer", "lme4"), dependencies = TRUE)
library(wooldridge)
library(plm)
#> Le chargement a nécessité le package : Formula
library(lme4)
#> Le chargement a nécessité le package : Matrix
data(wagepan)
第一个示例是一个简单的线性模型，忽略了组
nr。使用lme4不能做到这一点，因为没有“随机效应”（在
lme4意义上）。这就是Gelman＆Hill所谓的完整合并方法。
Pooled.ols <- plm(lwage ~ educ + black + hisp + exper+I(exper^2)+ married +
union + factor(year), data = wagepan,
index=c("nr","year"), model="pooling")
Pooled.ols.lm <- lm(lwage ~ educ + black + hisp + exper+I(exper^2)+ married + union +
factor(year), data = wagepan)
您的第二个示例似乎等效于
nr的随机截距混合模型作为随机效应（但所有预测变量的斜率是固定的）。
这就是Gelman＆Hill所谓的部分合并方法。
random.effects <- plm(lwage ~ educ + black + hisp + exper + I(exper^2) + married +
union + factor(year), data = wagepan,
index = c("nr","year") , model = "random")
random.effects.lme4 <- lmer(lwage ~ educ + black + hisp + exper + I(exper^2) + married +
union + factor(year) + (1|nr), data = wagepan)
您的第三个示例似乎与
nr是固定效果并且您为每个组计算不同的
nr截距。再说一遍：您不能使用
lme4这样做，因为没有“随机效应”（在lme4意义上）。这就是Gelman＆Hill所谓的“无池”方法。
fixed.effects <- plm(lwage ~ I(exper^2) + married + union + factor(year),
data = wagepan, index = c("nr","year"), model="within")
wagepan$nr <- factor(wagepan$nr)
fixed.effects.lm <- lm(lwage ~ I(exper^2) + married + union + factor(year) + nr,
data = wagepan)
比较结果：
stargazer::stargazer(Pooled.ols, Pooled.ols.lm,
random.effects, random.effects.lme4 ,
fixed.effects, fixed.effects.lm,
type="text",
column.labels=c("OLS (pooled)", "lm no pool.",
"Random Effects", "lme4 partial pool.",
"Fixed Effects", "lm compl. pool."),
dep.var.labels = c("log(wage)"),
keep.stat=c("n"),
keep=c("edu","bla","his","exp","marr","union"),
align = TRUE, digits = 4)
#>
#> =====================================================================================================
#> Dependent variable:
#> ----------------------------------------------------------------------------------------
#> log(wage)
#> panel OLS panel linear panel OLS
#> linear linear mixed-effects linear
#> OLS (pooled) lm no pool. Random Effects lme4 partial pool. Fixed Effects lm compl. pool.
#> (1) (2) (3) (4) (5) (6)
#> -----------------------------------------------------------------------------------------------------
#> educ 0.0913*** 0.0913*** 0.0919*** 0.0919***
#> (0.0052) (0.0052) (0.0107) (0.0108)
#>
#> black -0.1392*** -0.1392*** -0.1394*** -0.1394***
#> (0.0236) (0.0236) (0.0477) (0.0485)
#>
#> hisp 0.0160 0.0160 0.0217 0.0218
#> (0.0208) (0.0208) (0.0426) (0.0433)
#>
#> exper 0.0672*** 0.0672*** 0.1058*** 0.1060***
#> (0.0137) (0.0137) (0.0154) (0.0155)
#>
#> I(exper2) -0.0024*** -0.0024*** -0.0047*** -0.0047*** -0.0052*** -0.0052***
#> (0.0008) (0.0008) (0.0007) (0.0007) (0.0007) (0.0007)
#>
#> married 0.1083*** 0.1083*** 0.0640*** 0.0635*** 0.0467** 0.0467**
#> (0.0157) (0.0157) (0.0168) (0.0168) (0.0183) (0.0183)
#>
#> union 0.1825*** 0.1825*** 0.1061*** 0.1053*** 0.0800*** 0.0800***
#> (0.0172) (0.0172) (0.0179) (0.0179) (0.0193) (0.0193)
#>
#> -----------------------------------------------------------------------------------------------------
#> Observations 4,360 4,360 4,360 4,360 4,360 4,360
#> =====================================================================================================
#> Note: *p<0.1; **p<0.05; ***p<0.01
Gelman A，Hill J（2007）使用回归和多层次/层次模型进行数据分析。剑桥大学出版社
（一本非常非常好的书！）
由reprex package（v0.2.0）于2018-03-08创建。