There are a variety of approaches to improve the speed at which large RFID tag populations are being identified. In this paper, we present a transmission control strategy for a common class of RFID multiple access schemes. It builds on earlier work on Bayesian broadcast strategies, but has been adapted to address characteristics of the RFID domain. It has been designed for framed ALOHA and it makes no restrictive assumptions about the distribution of the number of tags in the range of the interrogator. Experimental evidence and simulation results are presented showing that the proposed transmission control scheme performs well in practise when compared to existing approaches.