dear R developers: may I suggest that you add to the various error messages that relate to "non-conformable arguments" (e.g. matrix multiplication) or "not multiple of"(e.g., comparison) the actual two dimension numbers that do not match up? something like Error in t(a) %*% vcov(reg.model) : non-conformable arguments to Error in t(a) %*% vcov(reg.model) : non-conformable arguments (0, 5) regards, /ivo