粗化精确匹配

Question

我正在尝试对包含 6549 个观测值和 94 个变量的数据集运行粗化精确匹配。我已经消除了 NA，并且正在“Polity2>/7”（治疗）上运行匹配。但是，当我开始运行命令时，我遇到了以下错误消息：

mat<-cem(treatment="Polity2>=7",data = Matched2a, drop = "todrop")

Error in names(obj$group.idx) <- paste("G", obj$g.names, sep = "") : 

'names' attribute [1] must be the same length as the vector [0]

In addition: Warning messages:
1: In reduce.var(data[[i]], cutpoints[[vnames[i]]]) :
  NAs introduced by coercion
2: In reduce.var(data[[i]], cutpoints[[vnames[i]]]) :
  NAs introduced by coercion

有人可以向我解释这些错误消息的含义吗？

Answer 1

确保将处理变量列添加到数据中。