An employee that wants to sue a current or former employer cannot always just file a lawsuit in court. For a significant number of employment claims, an employee is first required to file a “Charge” with the Equal Employment Opportunity Commission (“EEOC”) — and then, only after the EEOC has concluded an investigation, can the employee proceed with a lawsuit. Among the claims that an employee must file with the EEOC are those for retaliation.

Charges of retaliation outnumber all other types of cases handled by the EEOC. Retaliation in the employment context essentially means that an employer is punishing an employee — by disciplining them, demoting them, firing them, etc. — because the employee came forward to the employer and made a protected complaint. A protected complaint can be an allegation of harassment or discrimination in the workplace.

It is very rare to have a retaliation case that involves what lawyers call “direct evidence.” This means that an employee in a retaliation case can rarely produce “hard” evidence that would show that the employer fired them because of their complaint, such as an admission in an email, a letter, a voicemail message, or any other type of “smoking gun” piece of evidence.

Instead, retaliation cases require the plaintiff to prove three things. First, the plaintiff has to show that he/she made a protected complaint. Second, the plaintiff has to show that he/she suffered from an adverse employment action — i.e., a change in the terms and conditions of employment such as a demotion, suspension, or termination. And, third, the plaintiff has to establish a causal link between the complaint and the adverse employment action.

The most disputed issue in a retaliation lawsuit is the third element — proving a causal link. And the most important piece of evidence in establishing the causal link is timing. If the adverse employment action happened within days of the protected complaint, then the plaintiff’s case is relatively strong. However, if a substantial period of time has elapsed between the adverse employment action and the protected complaint, then the employer can seek summary judgment and try to get the case dismissed based on the argument that the prolonged gap in time means between the complaint and the adverse employment action are not causally connected.

Recently, a federal court in New York dismissed a retaliation lawsuit precisely because of the significant gap in time between when the employee had complained about the employer’s alleged wage and hour law violations and the employee’s termination. In Straebler v. NBC Universal, Inc., the United States District Court for the Southern District of New York ruled that the plaintiff’s complaint did not state a “plausible” claim for retaliation where there was a 13-month gap between the employee’s complaints about alleged wage and hour violations and the termination. The judge explained that the case had to be dismissed because, absent other factual allegations, the gap in time of more than a year between the protected complaint and the termination could not provide enough of a basis for a retaliation claim.

The bottom line is that if an employee has come to you with a complaint, you have to be very cautious about how you treat that employee. This is true, even if you conduct an internal investigation and determine that the employee’s complaint has no merit. Taking any action against an employee who has complained — especially terminating such an employee — is often tantamount to inviting litigation.