user2502904 user2502904 - 16 days ago 5
R Question

R language package ltm issue with library command

I am hoping the someone can answer a short question on ltm.

ltm installs successfully with


but the library command:


throws this error:

Error: package ‘polycor’ required by ‘ltm’ could not be found

I cannot locate polycor in the install.packages menu in RStudio.

This documentation on ltm: does not mention polycor

I have used this package before without a problem, but it has been about one year since I last used it.



You may need to update R. From CRAN polycor info it says the package depends on R>3.3.0. Additionally, this site may help.

If you are using linux, you should be able to type: R --version into a terminal to confirm which version you have

edit: though it appears my R version is 3.2.3...I may need to change my ubuntu repo

 sudo apt-cache showpkg r-base
 sudo apt-get upgrade r-base
 sudo apt-get install r-base