# R code for the Bowie (2001) Waldorf (ay) study, from Gorman and Johnson 
# in press

source('ky.R')
library(MASS)
library(Design)
library(mlogit)
options(contrasts = c('contr.sum', 'contr.poly'))

waldorf <- read.csv('waldorf.csv')
waldorf$stress <- as.factor(waldorf$stress)

# mlogit
m.waldorf <- mlogit.data(waldorf, "response", "wide")
contrasts(m.waldorf$following) <- contr.sum(12)
contrasts(m.waldorf$age) <- contr.sum(7)
contrasts(m.waldorf$gender) <- contr.sum(2)
contrasts(m.waldorf$syntactic) <- contr.sum(6)
contrasts(m.waldorf$stress) <- contr.sum(2)
summary(mlogit(response ~ 1 | following + age + gender + syntactic + stress, data=m.waldorf, ref.level="0"))

# proportional odds assumption table
summary(response ~ following + age + gender + syntactic + stress + style, data=waldorf, fun=sf)

# ordered logit model
waldorf$oresponse <- ordered(waldorf$response)
m0 <- polr(oresponse ~ following + age + gender + syntactic + stress + style, data=waldorf)
sum.coef(m0)