I am absolutely new to R and I am aware of only a few basic command lines. I was running a robust regression in R, using the following command line library (MASS) rfmodel2 <- rlm (TotalEmployment_2005 ~ ALABAMA + MISSISSIPPI + LOUISIANA + TotalEmployment_2000 + PCWhitePop_2005 + UnemploymentRate_2005 + PCUrbanPop2000 + PCPeopleWithACollegeDegree_2000 + PCPopulation.of.or.over.65.years.of.age_2005) summary (rfmodel2) But, it keeps giving me an error message as soon as I try to run it Error in rlm.default(x, y, weights, method = method, wt.method = wt.method, : 'x' is singular: singular fits are not implemented in rlm I used the above mentioned command line previously and it worked fine, but after I deleted a few observations, it started giving me this error. I even tried to change the setting to --no restore data- but that did not work either. I am a beginner, so it would be really helpful if someone could explain this error to me. Thanks! -- View this message in context: http://r.789695.n4.nabble.com/Singular-error-in-rlm-tp2327718p2327718.html Sent from the R help mailing list archive at Nabble.com.