Track discipline by supervisor--often the most important factor when courts weigh bias cases.

Courts want to see that workers are treated fairly and equally. But they also understand that standards may vary depending on the supervisor. That's why, when deciding whether discipline was biased, courts are likely to compare workers who have the same supervisor instead of all workers who have the same job.

That makes it important to track discipline by supervisor. If an employee sues, alleging that workers outside his protected class received more favorable treatment, you will be able to...