Whether you’re just starting out or about to go public with your union, questions of who’s in and who’s out are bound to be constant. There are several criteria that make some workers ineligible to unionize, but one of the most common is the line that divides you from a manager or supervisor. The factors that classify someone as a manager or supervisor may not always be so clearcut, but there are general differences that can help you narrow your list down.

We’ll be pulling from this Congressional Research Report, which digs into the present day nuances at length, but first, let’s start with the overarching legal definition of a supervisor. This is from the National Labor Relations Act (NLRA) passed in the 1930s:

“The term ‘supervisor’ means any individual having authority, in the interest of the employer, to hire, transfer, suspend, lay off, recall, promote, discharge, assign, reward, or discipline other employees, or responsibly to direct them, or to adjust their grievances, or effectively to recommend such action, if in connection with the foregoing the exercise of such authority is not of a merely routine or clerical nature, but requires the use of independent judgment.

If your coworker fits this definition, then they can’t legally be a member of your union. While sympathetic supervisors are always appreciated, they should be careful! Supervisors who publicly support a union drive aren’t protected under U.S. law. They could be both fired for supporting an organizing effort and also hurt a campaign’s legitimacy if it's believed that a supervisor pressured anyone to sign a card.

As we’re sure you’ve learned, things aren't so black and white. For example, tugboat captains aren't considered supervisors. However, it can get pretty murky when workers hold minor supervisory roles in other areas. Plus in the 2001 decision out of National Labor Relations Board (NLRB) v. Kentucky River Community Care, Inc., the Supreme Court found that the burden of proof lies with whichever side, whether union or management, first makes the claim of a worker’s status as a supervisor or otherwise. In other words, before you tell the NLRB who belongs in your union, you need to have a good sense of the roles and responsibilities of the workers you choose to include and exclude. There’s a chance you may need to back it up down the line.

So, let’s break this definition down into its key parts

1.) “‘supervisor’ means any individual having authority” and “requires the use of independent judgment”

From the outset, you should have noticed that job titles have no bearing on whether or not a coworker can join your union. It has to do with the power and responsibility of the position. Both Supreme Court case law and National Labor Relations Board (NLRB) decisions have debated and shaped the extent of these workplace framings.

To have independent judgement in the NLRB’s view, a supervisor must be free of the control of others to act on behalf of the company when evaluating a colleague or affecting their material and workplace conditions. The original definition of supervisor in the NLRA makes clear that such authority on the job must be a permanent part of a worker's duties and “not merely routine or clerical nature.” Quoting here from that Congressional Report mentioned above;

“If there is only one obvious and self-evident choice ... or if the assignment is made solely on the basis of equalizing workloads, then the assignment is routine or clerical in nature and does not implicate independent judgment.”

According to U.S. law, supervisory duties must account for at least 10-15 percent of a worker’s time for them to be viewed as a supervisor and therefore be non-eligible to unionize. When mapping out your workplace, think about your grey-area colleagues through this lens. Maybe they spend a half hour each morning setting the schedules of other workers or independently make decisions about which grants your nonprofit should apply for. Don't get too tripped up on this question in the beginning.

Now, onto the second key part of the NLRA definition.

2.) “to hire, transfer, suspend, lay off, recall, promote, discharge, assign, reward, or discipline other employees, or responsibly to direct them, or to adjust their grievances, or effectively to recommend such action”

This section is a bit more straightforward. If hiring, firing, or affecting the material conditions of another worker is an integral part of your job, then you can’t unionize. The above-listed description is a checklist of responsibilities worth running through as you determine each of your coworkers’ eligibility to unionze. Again, quoting from the Congressional Report;

“the person directing and performing the oversight of the employee must be accountable for the performance of the task by the other, such that some adverse consequence may befall the one providing the oversight if the tasks performed by the employee are not performed properly.”

3.) Some closing advice

Be sure to build an accurate list, but prioritize building support with your peers and people who you know are eligible for the union. While it’s better to be safe than sorry, if a reasonable case can be made that they should be in your union and are supportive, there’s no need to turn someone away at the outset. In contrast, if you think there will be supervisory issues with a worker on your list, you can and should discuss those with the people in those positions. Don’t leave them out, but don’t make any promises either.

Check in with your pro-union coworkers who may have a better sense of the colleague in question’s role. If you’re still unsure and it’s very case specific then there could be precedents in your industry that shape how you approach it.