[R] Multinomial Logit Model with lots of Dummy Variables
ghpow1
ghpow1 at student.monash.edu.au
Sun Apr 10 11:37:34 CEST 2011
Hi All,
I am attempting to build a Multinomial Logit model with dummy variables of
the following form:
Dependent Variable : 0-8 Discrete Choices
Dummy Variable 1: 965 dummy varsghpow at student.monash.edu.augh@gp1.com
Dummy Variable 2: 805 dummy vars
The data set I am using has the dummy columns pre-created, so it's a table
of 72,381 rows and 1770 columns.
The first 965 columns represent the dummy columns for Variable 1
The next 805 columns represent the dummy columns for Variable 2
My code to build the mlogit model looks like the following. I want to
know...is there a better way of doing this without these huge equations? (I
probably also need a more powerful PC to do all of this).
I'll also want to perform a joint test of significance on the first 805
coefficients...
Is this possible?
Thanks
GP
[code]
#install MLOGIT
library(mlogit)
#load mydata
mydata = 0
mydata<-read.csv(file="G:\\data.csv",head=TRUE)
my_data=0
num.rows=length(mydata[,1])
num.cols=965+805+1
my_data=matrix(0,nr=num.rows,nc=num.cols)
for(i in 1:num.rows) {
nb=mydata[i,2]
np=mydata[i,3]
my_data[i,nb]=1
my_data[i,965+np]=1
my_data[i,1+1770]=mydata[i,1]
}
#convert matrix to data.frame
# convert to data frame
my_data_frame<-as.data.frame(my_data)
#check data frame headers
head(my_data_frame)
#load dataframe into mldata with choice variable
mldata<-mlogit.data(my_data_frame, varying=NULL, choice="V1771",
shape="wide")
#V1771 = dependent var
#V1-V965 = variable 1 dummies
#V966-V1700 = variable 2 dummies
#regress V1771 against all 1700 variables...
mlogit.model<-mlogit(V1771~0|V1+V2+V3...+V1700,data=mldata, reflevel="0")
[/code]
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