Causation can be proved either by direct evidence or by an inference. Direct evidence is evidence that the employer was mad about the protected activity. If you or another witness saw a supervisor spout off about someone reporting a violation, that is direct evidence of the employer's animus against protected activity. Similarly, if the employer announces that whoever calls the SEC will be fired, or warns employees against reporting violations, that is direct evidence of retaliation. However, the Department of Labor recognizes that most employers are smart enough to suppress direct admissions of their motives. So, the Department can find causation based on inferences. For example, if the worker calls the SEC, and you can prove that the employer had an idea about who called, and that worker is fired shortly thereafter, the timing can support an inference that the protected activity caused the discharge. The timing can support an inference of retaliation when it is as long as six months or a year from the employer's discovery of the protected activity. An inference of causation can also be drawn from an employer's failure to follow normal procedures, use of false evidence, changing explanations, or a pattern of adverse actions after employees engage in protected activity.