Tom Willems <Tom.Willems <at> var.fgov.be> writes: > I have a question about the Akaike Information Criterion in the R > output. > Normally you would want it to be as small as possible, yet when i check up > the information in my study books, the AIC is usually displayed as a > negative number. In the exercises it is given as " - AIC ". > R displays it as a positive number, does this mean that a large "AIC" > gives a small " - AIC ", so the bigger the better? >
I don't know about your books, but confirm that smaller AIC is better. AIC is usually positive (likelihood is between 0 and 1, therefore log-likelihood is negative, therefore -2L + 2k is positive), although continuous probability densities or neglected normalization coefficients can lead to negative AICs -- but smaller (more negative, if AIC<0) is still better. Ben Bolker ______________________________________________ R-help@stat.math.ethz.ch 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.
