Tips for judging sincerity of employee's religious beliefs
In many situations, the question of whether an employee's request for a religious accommodation is tied to sincere religious beliefs isn't at issue. Instead, you simply need to assess whether you can provide the accommodation without causing an undue hardship. When you do question whether the employee sincerely holds the beliefs—e.g., if she raises a dubious religious objection to getting the COVID-19 vaccine—you should look to the Equal Employment Opportunity Commission's (EEOC) long-standing guidance on the level of inquiry you can make.
What are 'religious' beliefs and practices?
According to the EEOC, religious practices include the "moral or ethical beliefs as to what is right and wrong which are sincerely held with the strength of traditional religious views." Religion typically concerns "ultimate ideas" about "life, purpose, and death."
The EEOC doesn't protect beliefs merely because they're strongly held. Whether a practice is religious depends on the employee's motivation. Social, political, or economic philosophies, as well as personal preferences, aren't protected as religious beliefs under Title VII of the Civil Rights Act of 1964.
The EEOC does grant employees the benefit of the doubt. You shouldn't dismiss the beliefs simply because (1) the employee's practices deviate from the exact tenets of a religion or (2) few or no people adhere to them.
The definition of "religion" is broad, according to the EEOC, and you aren't likely to be familiar with every tenet. As a result, you should assume the request for a religious accommodation is based on a sincerely held religious belief.