 Policies can also be evaluated using a measure of fairness.The probability generating function of the stationary queue length distribution is given by the Pollaczek–Khinchine transform equation
where g("s") is the Laplace transform of the service time probability density function.In the case of an M/M/1 queue where service times are exponentially distributed with parameter "μ", g("s") = "μ"/("μ" + "s").