"Generalized Linear Models Theory ⇒ Log-Likelihood Functions" in the Details section of the SAS 9.2 GENMOD procedure documentation discusses the Log Likelihood and Full Log Likelihood statistics produced by the GENMOD procedure. The formulas show that the Full Log Likelihood does not involve the dispersion parameter (φ) for the binomial, multinomial, and poisson distributions. Since these distributions do not have dispersion parameters, the formulas shown are the correct log likelihood functions for those distributions. However, for each of these distributions, GENMOD divides the formulas shown by φ. As a result, the Full Log Likelihood value is affected by the SCALE= option. Since the AIC and BIC fit statistics are based on the Full Log Likelihood, they are also affected.