In this study, we derive an analytical model that determines the conditions that lead to throughput-starvation in Wimax-based networks. We limit our discussion to downlink traffic in point-to-multipoint (PMP) based networks. The objective of our model is to define the probability of a subscriber station becoming throughput starved under different operating conditions. The model also defines the probability of a subscriber station being throughput overserved under the same operating conditions. We validate the resulting model using simulation experiments.