A method and system for determining low error rate behavior of a device are provided. In one implementation, the method includes obtaining a dominant trapping set of a code, the dominant trapping set containing a plurality of variable nodes, and biasing bits associated with a programmable transmitter that is in communication with the device. The biased bits correspond to the variable nodes of the dominant trapping set. The method further includes transmitting random data from the programmable transmitter to the device, in which the random data includes one or more of the biased bits; measuring a number of error events corresponding to biased bits received by the device that cannot be decoded; and determining a true bit error rate of the device based on the measured number of error events.