Hi Jeremy, I think Jessica is right that probably you could make polr converge and produce a Hessian if the data are better scaled, but there might also be other things not allowing you to get the Hessian/vcov. Could be insightful if you showed us the result of str(Jdata)
Also, I am thinking that perhaps the another implementation of ordinal regression models might avoid the problem. You could try the ordinal package (of which I am the author) -- the following should reproduce the MASS::polr results: install.packages(ordinal) library(ordinal) Global <- clm(JVeg5 ~ Elevation + Lat_Y_pos + Coast_dist + Stream_dist, data=Jdata) summary(Global) Another option would be Frank Harrell's lrm function in the rms package. HTH, Rune On 9 July 2012 11:55, Jeremy Little <jeremy.lit...@my.jcu.edu.au> wrote: > Hello, > > I am trying to run an ordinal logistic regression (polr) using the package > 'MASS'. > > I have successfully run other regression classes (glm, multinom) without > much problem, but with the 'polr' class I get the following error: > " Error in svd(X) : infinite or missing values in 'x' " > which appears when I run the "summary" command. > > The data file is large (585000 rows) and has no NA, -9999 or blank values. > > My script (in brief) is as follows, with results: > > ############ >> library(MASS) >> >> ## ADD DATA >> Jdata<- read.delim("/Analysis/20120709 JLittle data file.txt", header=T) >> >> attach(Jdata) >> names(Jdata) > [1] "POINTID" "Lat_Y_pos" "JVeg5" "Subregion" "Rock_U_Nam" > "Rock_Name" "Elevation" "Slope" "Aspect" "Hillshade" > "Stream_dist" "Coast_dist" "Coast_SE" > [14] "Coast_E" "Wind_310" "TPI" "Landform" >> >> Global <- polr(JVeg5 ~ Elevation + Lat_Y_pos + Coast_dist + Stream_dist, >> data=Jdata) >> >> summary(Global) > Error in svd(X) : infinite or missing values in 'x' >> > ##Try with omit NA command >> Global <- polr(JVeg5 ~ Elevation + Lat_Y_pos + Coast_dist + Stream_dist, >> data=Jdata, na.action = na.omit, Hess = TRUE) >> >> summary(Global) > Error in svd(X) : infinite or missing values in 'x' > ############ > > Does this imply an 'infinite value' and what would this mean? > > If anyone has any idea how to address this error, I would very much > appreciate your response. > > Thank you in advance. > > Jeremy > > Date File Attachment (200 rows): > http://r.789695.n4.nabble.com/file/n4635829/20120709_JLittle_data_file.txt > 20120709_JLittle_data_file.txt > > > -- > View this message in context: > http://r.789695.n4.nabble.com/Package-MASS-polr-Error-in-svd-X-infinite-or-missing-values-in-x-tp4635829.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. -- Rune Haubo Bojesen Christensen Ph.D. Student, M.Sc. Eng. Phone: (+45) 45 25 33 63 Mobile: (+45) 30 26 45 54 DTU Informatics, Section for Statistics Technical University of Denmark, Build. 305, Room 122, DK-2800 Kgs. Lyngby, Denmark ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.