I found this question on Quora.
Here’s my answer:
Bias has wrong in its definition.
If you’re trying to find a right answer to a question, you use some sort of process to discover the answer. Bias is the word for parts of that process that cause it to sometimes give wrong answers.
Often bias comes up when talking about race relations. If you are trying to determine who would be a good employee from among several, you will probably rely partly on your gut feelings. But without your knowing it, your gut feelings give wrong answers about some people because they pay attention to race inappropriately. That is bias in your “gut feelings” system.
There are times when race needs to be taken into account, such as when casting an acting role. In this case paying attention to race is not a bias and not wrong. But many times, acting roles do not actually call for a specific race. In those cases, paying attention to race is a bias and therefore likely to not result in hiring the best candidate for the role.