lavaan WARNING: correlation between variables is (nearly) 1.0

[Franciosalgeo]

Hi everyone,

I run a sem function for mediation analysis, and I got the warning in lavaan 

lavaan WARNING: correlation between variables stn and intake is (nearly) 1.0. Here stn is my dependent variable with two categories (1/2), and intake is the continuous depend variable. Should I worry about this warning?

Thanks,

Francio

[Terrence Jorgensen]

Sounds like stn=1 and stn=2 have intake values that nearly do not overlap.  When they do not overlap at all, then the variables are redundant, so you can't fit a model to it.  

https://stats.idre.ucla.edu/other/mult-pkg/faq/general/faqwhat-is-complete-or-quasi-complete-separation-in-logisticprobit-regression-and-how-do-we-deal-with-them/

Terrence D. Jorgensen

Assistant Professor, Methods and Statistics

Research Institute for Child Development and Education, the University of Amsterdam

http://www.uva.nl/profile/t.d.jorgensen

 

[Franciosalgeo]

No, intake values are overlapping across stn. Intake has Mean±Sd 66.4 ± 10.41 for stn=1 and 64.76 ± 10.18 for stn=2. I have also checked range of intake in stn=1 and stn=2.