用于权衡的变量集改变了结果估计

Question

比较传递给 svyby 函数的变量集对结果估计值和标准误差的影响时，我发现权衡单个变量和两个变量会产生相同的估计值，但权衡多变量产生的估计值明显低于其他两种方法。

这是什么原因，我怎样才能避免这种情况发生？

Link 到数据集：https://drive.google.com/open?id=1xqFxUBLZifaz57yvoNFOcvhBDGuHuSMq

这是我的代码：

library(tidyverse)
library(survey)

load("des2004small.RData")

weighUp <- function(variables) {
  svyby(formula = make.formula(variables), by = ~statefip, 
        design = des2004small,  
        FUN = svytotal, na.rm = TRUE)
}

# Weigh up a single variable:
dfstate2004_singleVariable = weighUp(c("race_acs"))
# Weigh up two variables:
dfstate2004_twoVariables = weighUp(c("race_acs", "cvap_acs"))
# Weigh up multiple variables:
dfstate2004_multipleVariables = weighUp(c("race_acs", "cit_acs", 
                                          "educ_acs", "unemployed_acs", "labforce_acs", "poverty_acs", "cvap_acs"))

# Compare the three diffent methods:
comparison2004 = dfstate2004_singleVariable %>% 
  inner_join(dfstate2004_twoVariables, by = "statefip", suffix = c(".single", ".two")) %>%
  inner_join(dfstate2004_multipleVariables, by = "statefip", suffix = c("", ".multiple"))

race_acswhite2004 = comparison2004 %>% 
  select(statefip, 
         single = race_acswhite.single, 
         two = race_acswhite.two, 
         multiple = race_acswhite)
race_acswhite2004

以下是不同的估计结果：

+-------------------------------------+
|   statefip  single     two multiple |
+-------------------------------------+
| 1        1 3084123 3084123  2128346 |
| 2        2  427008  427008   277075 |
+-------------------------------------+

Answer 1

'multiple' table 中的变量有缺失值，svytotal 丢弃任何变量中的缺失值观察值它正在分析。好吧，默认情况下它会给出 NA 结果，但是如果你要求它使用 na.rm=TRUE 删除缺失值，它会删除它们和整个观察结果。

用于权衡的变量集改变了结果估计

The set of variables used for weighing-up changes the resulting estimates

r

survey