Very simple (and flawed) IV estimation

ivest.R

library(AER)
library(lmtest)
data("CollegeDistance")
cd.d<-CollegeDistance
simple.ed.1s<- lm(education ~ distance,data=cd.d)
cd.d$ed.pred<- predict(simple.ed.1s)
simple.ed.2s<- lm(wage ~ urban + gender + ethnicity + unemp + ed.pred , data=cd.d)
simple.comp<- encomptest(wage ~ urban + gender + ethnicity + unemp + ed.pred , wage ~ urban + gender + ethnicity + unemp + education , data=cd.d)
1s.ftest<- encomptest(education ~ tuition + gender + ethnicity + urban , education ~ distance , data=cd.d)


library(arm)
coefplot(lm(wage ~ urban + gender + ethnicity + unemp + education,data=cd.d),vertical=FALSE,var.las=1,varnames=c("Education","Unemp","Hispanic","Af-am","Female","Urban","Education"))
coefplot(simple.ed.2s , vertical=FALSE,var.las=1,varnames=c("Education","Unemp","Hispanic","Af-am","Female","Urban","Education"))