Whom do you consider to be supervisors at your company? It's a question you'll have to take a fresh look at in light of a new U.S. Supreme Court decision.
The Court upheld the National Labor Relations Board (NLRB) position that whoever claims a worker is a supervisor bears the burden of proof. If you claim workers are ineligible to be included in union bargaining units because they are supervisors, be prepared to back up that position. If the NLRB's general counsel tries to hold you liable for some actions because it says employees were acting on your behalf as supervisors, then he has the burden to prove it.
The justices, however, struck down the NLRB's decision that registered nurses at a mental health center weren't supervisors because they didn't exercise enough "independent judgment" in directing the work of less-skilled employees. The NLRB said they were using only "ordinary professional or technical judgment." (NLRB v. Kentucky River Community Care Inc., No. 99-1815)
The National Labor Relations Act defines a supervisor as someone who, in his employer's interest, uses independent judgment to exercise one of 12 functions: hire, transfer, suspend, lay off, recall, promote, discharge, assign, reward or discipline other employees, direct them or adjust their grievances, or effectively recommend such action.
The Court's majority noted that it's still ambiguous how much discretion is required to illustrate a worker's "independent judgment."