Understanding Past Practice In Labor Law
When you work in labor relations long enough, you learn that past practice is basically whatever has been done consistently without objection for a reasonable period of time. It sounds simple but it is one of the most disputed concepts in grievance arbitration. The tricky part is figuring out what counts as consistent, what counts as an exception, and whether a practice actually overrides written contract language. I spent years dealing with this during contract negotiations and arbitration hearings. One particular case stands out. We had a company that had given holiday pay to all employees for fifteen years. The contract said nothing about holiday pay. When management decided to stop it, the union grieved immediately claiming past practice. The arbitrator ruled against us because the practice was consistently followed and never formally objected to. It did not matter that the contract was silent. Past practice filled the gap.
How Past Practice In Labor Law Actually Works
To establish past practice, you need three elements. First, the practice must be clear and established. Second, it must be consistent over time. Third, both sides must have accepted it without objection. If any of these are missing, the claim falls apart. The longer the practice has existed, the stronger the presumption that it is binding. Here is where beginners usually mess up. They think any repeated action becomes a practice. That is wrong. If an employer occasionally does something different for legitimate business reasons, that does not break the practice. The key is whether the action was an exception or a new standard. I once saw a company lose a grievance because a supervisor gave a favor once. The union claimed it was now a practice. The arbitrator disagreed because there was no evidence of consistency or mutual acceptance. The real danger with past practice is that it can modify your contract even when the written language is clear. Some people think a clear contract cannot be changed by practice. That is not true in labor arbitration. If both sides have acted consistently under a contract for years, the practice becomes part of the agreement whether you like it or not. This is why I always recommend tracking every deviation from policy and documenting the reason. A simple email saying "this is a one-time exception due to..." can save you a lot of trouble later.
There are limitations you should know about. Past practice does not override mandatory arbitration clauses or statutory requirements. If the law says something must be done a certain way, practice cannot change that. Also, past practice cannot create obligations that were never negotiated. If the union never accepted the practice, it may not bind them. These edge cases come up more often than you would think. I usually advise clients to review their past practices during every contract negotiation. Write down what you have been doing consistently. Identify any exceptions. If there is something you want to stop, negotiate it out explicitly. Do not assume the current practice will survive the new contract. Most arbitrators will continue to apply it unless the new language clearly contradicts it. This usually takes about two hours of preparation but can save months of grievance proceedings later. If past practice does not work for your situation, consider using a memorialization clause instead. This explicitly incorporates certain practices into the contract. It is more stable than relying on implied practice but requires more negotiation effort upfront. You get clarity but lose flexibility. That tradeoff is worth understanding before you commit to either approach.
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