RFID system components, such as readers and tags, communicate where the reader inventories a population of tags. The reader evaluates responses from tags by categorizing them in slots. As tags are inventoried, the number of slots based on a Q-parameter is reduced. The reader determines an interim value for the Q parameter, generates a Q1 value by applying the interim value to a damping function, and uses the Q1 value in another round of interrogation. The reader then determines whether to increase or decrease the interim value depending on the tag replies. The increase or decrease may be an increment or a decrement such as incrementing or decrementing a floating point number of the interim value in a damping function that is arranged to return an integer by rounding the floating point number.