Whether or not data are biased depends on what you want to measure. If you are trying to measure the arrest rate, then the arrest rates are an unbiased predict

Whether or not data are biased depends on what you want to measure. If you are trying to measure the arrest rate, then the arrest rates are an unbiased predictor. If you are trying to measure the true crime rate, then the arrest rates are a biased predictor. I certainly agree that racially motivated arrests are a large issue, and should be dealt with. Avoiding misinterpreting data is a widespread issue that in these cases happens to have prejudicial consequences.