You forget the last source of bias : the bias could be on a lower level. For instance, there could be some sort of bias, hidden to the algorithm, that makes cer

You forget the last source of bias : the bias could be on a lower level. For instance, there could be some sort of bias, hidden to the algorithm, that makes certain decisions succeed and others fail in a biased way, but for instance if we're talking companies, state-backed companies succeed, foreign companies suddenly fail. There could be a real world bias.