Causation is part of every employment discrimination case. Causation means that there is a link between the employment action and a discriminatory reason. For example, if a worker is fired because the worker was caught stealing from the employer, the decision to terminate the worker is legitimate, not discriminatory. But, if the employer terminates a worker because the worker is 60 years old, there is a link between the decision to terminate and a discriminatory motivation for the decision.
The law provides different standards of causation. Sometimes, discrimination must be a determinitive factor in the decision to take action against the employee, meaning that the employer would not make the same employment decision without a discriminatory animus present. This is usually referred to as “but for” causation. Other times, the law says that the discrimination can be one of many factors, usually called a mixed-motive or motivating factor standard.
Many employment discrimination laws, particularly federal laws, do not spell out which type of causation is required. So, courts are left to interpret the appropriate level of causation. Recently, led by Supreme Court decisions, courts have been applying but-for causation to discrimination cases, except in circumstances where Congress has expressly acted to convey its intent that some other level of causation applies. Based on the decisions, we have clarity that but-for causation applies to age discrimination and retaliation claims. Motivating factor applies to federal Title VII claims (race, religion, sex, national origin).