Dear R users Today I discovered that function lm.influence() stops when applied to glm objects with the following error message
Error in if (NROW(e) != n) stop("non-NA residual length does not match cases used in fitting") : argument is of length zero After inspecting lm.influence.R (both into R-2.10.1.tar.gz and R-patched.tar.gz) i found (line 53) that n is computed as n <- as.integer(nrow(model$qr$qr)) However, glm objects (differently from lm objects) do not have a $qr component. Is this intentional, i.e. it means that we have to use lm.influence only with glm objects? It could be, but I remark that the lm.influence{stats} help says: The influence.measures() and other functions listed in See Also provide a more user oriented way of computing a variety of regression diagnostics. These all build on lm.influence. Note that for GLMs (other than the Gaussian family with identity link) these are based on one-step approximations which may be inadequate if a case has high influence. Moreover, if we have to use such a function only with lm objects, I would suggest to implement some more explicit check. Thanks in advance for any help Fabrizio Cipollini ______________________________________________ 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.