cpi_oprobit.R

# File-Name:       cpi_oprobit.R                 
# Date:            2009-11-17                                
# Author:          Drew Conway                                       
# Purpose:         Quick ordered probit analysis of the Corruption Perceptions Index 2009
#                   to check for effect of number of surveys used on CPI scores
# Data Used:       corruption_index.csv
#  available here: http://www.drewconway.com/zia/wp-content/uploads/2009/11/corruption_index.csv
# Packages Used:   foreign,Zelig
# Output File:     
# Data Output:     
# Machine:         Drew Conway's MacBook                         
                                                                    
library(foreign)
library(Zelig)

#Get data
cpi<-read.csv('corruption_index.csv')

# Run ordered-probit, CPI scores are rounded so the dep vars are discrete integers
cpi.op<-zelig(as.factor(round(CPI.2009.Score))~Surveys.Used,data=cpi,model="oprobit")

# Get results
summary(cpi.op)