In this paper a quantitative analysis of a general feedback communication system is undertaken. The model considered is sufficiently general that the resulting analysis may be used when considering most feedback schemes. Mathematical expressions are derived for the probability of error and transmission efficiency of a feedback scheme when finite and infinite numbers of repetitions are possible, and also when the feedback channel can be considered noiseless or noisy. An example of single-symbol repetition on an additive white Gaussian noise channel is fully analysed.