One in five workers in the United States is age 55 or older, and 65% of workers say they’ve seen or experienced age discrimination in the workplace, according to the AARP.

Ageism is too common in today’s workplace, with stereotypes, derogatory remarks and preferential treatment of younger employees rampant. Not only is age discrimination offensive, but it’s also illegal.

What is age discrimination in the workplace?

Age discrimination is discrimination against an employee because of their age. The Age Discrimination Employment Act (ADEA) of 1967 makes age discrimination against any employee or person being interviewed for a job illegal. Since the passage of the ADEA, age has been considered a protected class, much like religion, race, ethnicity, nationality and sex. The law applies to government employees and private employers with 20 or more employees.

What does age discrimination look like? Examples include:

• Firing someone because they’re “too old” to work there any longer

• Refusing to hire a candidate on account of their age

• Promoting younger employees over older, more qualified ones

• Reducing the salaries of or demoting older employees for no reason other than age

• Taking away responsibilities from older employees on account of their age

• Telling age-related jokes or making disparaging comments about someone’s age

It’s important to note that the ADEA only protects employees age 40 and older from age-related discrimination. There is no U.S. law in place that protects younger employees from age-related discrimination. For example, if someone is not hired because they’re considered too young by the employer, this would not be characterized as age discrimination and is not illegal.

Bear in mind, too, that not all negative actions taken against someone age 40 or over are age discrimination, such as if performance or other factors are at play. For example, if a younger candidate is hired over an older one simply because they’re more qualified, this is perfectly acceptable. Moreover, if an employee over the age of 40 is fired because of their poor performance, that is within the employer’s rights, too.

10 signs of age discrimination

1. You notice older workers being replaced by younger workers.

This can take several forms. For example, the employer might eliminate older workers’ positions and lay these employees off, only to subsequently hire younger workers for very similar positions with just some minor adjustments. This is a way for employers to technically stay within the bounds of anti-discrimination laws. Or, you might wonder why all the new hires as of late seem to be on the younger side.

If you notice these and similar situations happening repeatedly, that’s a huge red flag.

2. Older workers are offered buyouts or (heavily) encouraged to vacate their positions.

The employer could be offering older workers buyouts to leave the company “voluntarily.” This is really no different from pushing them out, except that they’re trying to incentivize them to vacate their position rather than risk being sued for age discrimination. These buyouts can be quite generous, so they’re often enticing for employees who are offered them.

It is legal to set mandatory retirement ages in a small number of professions, where age could affect safety or the ability to perform the job. For example, airline pilots have a mandatory retirement age of 65. Some states have additional laws related to mandatory retirement age.

3. Employees are ridiculed because of their age or the victims of age-related jokes.

If you hear derogatory remarks about people’s ages, even if they seem to be meant in jest, this is ageism. These could come in the form of questions about when employees are planning to retire, comments about their memory not being up to par and so on. They can be pointed or subtle. People might intend for them to be funny and playful or quite cruel.

4. There is the assumption that older workers don’t understand or know how to do certain things.

Just because someone is over a certain age doesn’t mean they don’t know how to use a computer. But younger workers may assume that they’re not adept with technology and make comments to this effect.

5. Younger employees are offered professional development and learning opportunities, while older ones are not.

Older workers can appreciate professional development and learning opportunities just as much as younger ones. If an employer is reserving these types of training, workshops and other learning experiences for younger workers, the implication is that older workers are nearing the end of their careers and don’t want to build their skills. But people are working longer and longer these days, and it’s quite likely that they would appreciate having these opportunities, too.

6. Older employees are frequently passed over for promotions.

Like the previous sign, noticing that older workers are frequently being passed over for promotions in favor of younger ones who haven’t been at the organization as long could also indicate that ageism is at play, assuming that the older employees are more qualified than their younger counterparts.

7. Older employees are demoted.

Another way employers might try to skirt an age discrimination lawsuit is by downgrading or reassigning employee’s positions rather than outright laying them off or firing them. If their performance hasn’t suffered, then demotions could be less about the quality of the employee’s work than it is about the company’s desire to replace them with younger (and often less expensive) workers.

8. Challenging assignments are reserved for younger employees.

Often, taking away work from an employee could be an indication that they could be getting let go. It can also be a way to embarrass and frustrate an employee whom the employer is hoping will leave on their own. The implication is that the manager doesn’t trust the employee or think they’re capable of completing their work and makes them less useful and necessary to the company.

9. Younger employees don’t face the same criticism for similar mistakes that older employees make.

Employees deserve the same treatment, no matter what their age. While critiques are warranted sometimes, if the level of criticism for similar mistakes seems to be different for employees of different ages (for example, if it’s constructive for younger employees and just negative or even rude for older ones), then that’s not acceptable.

10. Your performance reviews were once glowing, but now they’re poor.

If you’re an older worker who has never received a negative performance review — in fact, they’ve been very positive in the past — and suddenly have a terrible one, that can be extremely jarring. And it’s highly unlikely that your performance suddenly plummeted.

If you’re unaware of any other factors that could have influenced this abrupt turnaround, it’s possible you’re the victim of age discrimination; management might be trying to push you out, using poor performance reviews as evidence of the rationale for doing so.

How age discrimination works

As discussed above, age discrimination can take many different forms, from making derogatory remarks and comments about an individual to firing someone for no reason other than age. Even if another employee is being ageist, the employer is still responsible and can be held accountable. While it’s impossible to outline how ageism works in every possible scenario, below are some instances in which there is potential for age discrimination and how it can be avoided.

Employers are not allowed to require the age of candidates on job applications unless there is a legitimate work-related reason for doing so. But that doesn’t prevent the hiring manager from assessing and potentially making judgment based on indicators like appearance and work history. If an interviewer asks questions based on age in the interview or chooses a younger, less-qualified candidate, this is a case of age discrimination.

Likewise, employees cannot be made to feel uncomfortable about their age or reassigned duties or responsibilities because of age-related circumstances. They cannot be fired, demoted or pushed out because of it, either. This, too, is age discrimination.

If you believe you’ve been the victim of age discrimination, you can file a complaint with the Equal Employment Opportunity Commission (EEOC). They will review and investigate your case. You do NOT need to wait for the EEOC to issue you a Notice of Right to Sue to file a lawsuit; you should simply file the suit in federal court 60 days after you filed the complaint with the EEOC.

You should also consult an employment attorney to discuss your case. They will advise you on how to best proceed and possible outcomes.

5 ways employers can prevent age discrimination

1. Read up on the laws.

In addition to the ADEA, educate yourself on the Age Discrimination Act of 1975, which prohibits discrimination due to age in programs that receive federal funding, and Section 188 of the Workforce Investment Act of 1998 (WIA), which prohibits discrimination against applicants, employees and participants in WIA Title I-financially assisted activities and programs.

Understanding the laws regarding employment-related age discrimination will help you avoid violating them, inadvertently or otherwise.

2. Go over your policies with a fine-tooth comb.

Consider hiring an employment attorney to consult and ensure compliance, too. You should also be looking at all areas where age bias could be occurring, such as in the hiring and recruitment process, employee development programs, training and onboarding, raises and promotions, PTO and others. Examine every policy and procedure to ensure that you’re addressing and working to prevent age discrimination.

3. Create professional development opportunities for everyone.

Provide and build on professional development opportunities that benefit everyone, not just younger employees. Consider creating a survey to distribute to your employees and ask them what they’re looking for in terms of developing career-related skills, growing their careers and improving their overall work and personal lives. Your employees’ ideas can help inform your programming and the opportunities you provide in the future.

4. Invest in anti-harassment and discrimination training.

Perhaps you already have anti-harassment and discrimination training for your employees — some states and cities require it. But does it address age discrimination? Make sure this too-prevalent problem is covered in your curriculum.

If you don’t already provide this training to employees, it’s time to start a program. Work with HR to create a training curriculum that uses real examples and scenarios that encompass different kinds of harassment and discrimination. This shouldn’t be limited to onboarding, either; employees need regular training to keep it fresh.

5. Establish a zero-tolerance anti-discrimination policy.

Discrimination is illegal. All employees must know that and be aware of what classes and groups are protected. Have a clear policy that thoroughly explains and defines discrimination and informs employees as to what the consequences of violations are. It should also outline the steps employees can and should take to report discrimination and what will happen once you do.

This policy should be posted in a visible location and be accessible to all employees via the employee handbook, your intranet and other digital locations. You should also remind employees of the policy regularly to help ensure that the workplace is staying safe and discrimination-free.

Written by Laura Berlinsky-Schine  for Fairygodboss.