Dear all, I have tried to merge two cross sections (crossA and crossB) as follows, both crossA and crossB include the same variables, e.g., ID,y,x1,x2: Panel <- merge(crossA,crossB,by="ID") I have, thereafter, tried to run the following pooled OLS: OLS <- lm(Panel$y~Panel$x1+Panel$x2) and have received the following error message "Error in model.frame(formula, rownames, variables, varnames, extras, extranames, : invalid variable type" I would be very grateful for help. At the moment, I believe that I have tried everything. Thanks in advance, Sophie
Have you tried the following: OLS <- lm(Panel$y~Panel$x1+Panel$x2, data=Panel) If yes, could you replicate the error with a small data set that you send with your help request? It can make it easier for others to diagnose. Hope this helps. spencer graves langensk at fas.harvard.edu wrote:> > Dear all, > > I have tried to merge two cross sections (crossA and crossB) as follows, both > crossA and crossB include the same variables, e.g., ID,y,x1,x2: > > Panel <- merge(crossA,crossB,by="ID") > > I have, thereafter, tried to run the following pooled OLS: > > OLS <- lm(Panel$y~Panel$x1+Panel$x2) > > and have received the following error message "Error in model.frame(formula, > rownames, variables, varnames, extras, extranames, : invalid variable type" > > I would be very grateful for help. At the moment, I believe that I have tried > everything. > > Thanks in advance, > Sophie > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help
I just see a difference between what I wrote and what I use. Have you tried the following: OLS <- lm(y~x1+x2, data=Panel) spencer graves ################### If yes, could you replicate the error with a small data set that you send with your help request? It can make it easier for others to diagnose. Hope this helps. spencer graves langensk at fas.harvard.edu wrote: > > Dear all, > > I have tried to merge two cross sections (crossA and crossB) as follows, both > crossA and crossB include the same variables, e.g., ID,y,x1,x2: > > Panel <- merge(crossA,crossB,by="ID") > > I have, thereafter, tried to run the following pooled OLS: > > OLS <- lm(Panel$y~Panel$x1+Panel$x2) > > and have received the following error message "Error in model.frame(formula, > rownames, variables, varnames, extras, extranames, : invalid variable type" > > I would be very grateful for help. At the moment, I believe that I have tried > everything. > > Thanks in advance, > Sophie > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help
I appreciate your help a lot. Unfortunately, none of your recommendations work. I have written a small program to illustrate my problems. I hope there is a solution... Cross1 <- data.frame(i=c(1,2,3),Y=c(3,2,2),X1=c(2,3,4)) Cross2 <- data.frame(i=c(1,2,3),Y=c(2,3,1),X1=c(5,6,7)) Panel <- merge(Cross1,Cross2,by="i") OLS <- lm(Panel$Y~Panel$X1) Thanks again for your help, Sophie -----Original Message----- From: Spencer Graves [mailto:spencer.graves at PDF.COM] Sent: den 21 april 2003 04:51 To: langensk at fas.harvard.edu Cc: r-help at stat.math.ethz.ch Subject: Re: [R] To create a Panel and run a Pooled OLS I just see a difference between what I wrote and what I use. Have you tried the following: OLS <- lm(y~x1+x2, data=Panel) spencer graves ################### If yes, could you replicate the error with a small data set that you send with your help request? It can make it easier for others to diagnose. Hope this helps. spencer graves langensk at fas.harvard.edu wrote: > > Dear all, > > I have tried to merge two cross sections (crossA and crossB) as follows, both > crossA and crossB include the same variables, e.g., ID,y,x1,x2: > > Panel <- merge(crossA,crossB,by="ID") > > I have, thereafter, tried to run the following pooled OLS: > > OLS <- lm(Panel$y~Panel$x1+Panel$x2) > > and have received the following error message "Error in model.frame(formula, > rownames, variables, varnames, extras, extranames, : invalid variable type" > > I would be very grateful for help. At the moment, I believe that I have tried > everything. > > Thanks in advance, > Sophie > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help