In 2020, COVID caused the most dramatic rise in unemployment the U.S. had ever seen. Employees who were lucky enough to avoid being laid off during the first few months of the pandemic largely hunkered down and resolved to stay with their current employer until the dust settled, even if they would otherwise have been looking to change jobs.

This led to a phenomenon in 2021 and 2022 called the Great Resignation, a period where hiring began opening up again. All of those employees who'd been itching for an exit saw an opportunity to make their move.

One of the interesting effects of this higher-than-normal employment migration in a relatively short period of time is tenure synchronization, where a large percentage of employees have been with the company for the same amount of time. Naturally, there will be some variation in when they decide to make their exits, but this synchrony does increase the chance of a mass exodus event once they've passed the year of average tenure.

There are other macroeconomic phenomena that are contributing toward sustained "phase locking" of the amplitude of employment migration. Post-pandemic, we saw an era of high inflation, and that caused many companies to veer back into more cautious territory and question whether they'd over-resourced themselves during the hiring boom. This led to rounds of layoffs in 2022 and 2023. These conditions have also led to downward pressure on wages. Thus, many employees are waiting until the next hiring wave to make their move.

These factors are likely to induce even more phase locking than the tenure synchonization alone, which means that we could see a second or even third "Great Resignation" event occur during the current decade as employees' synchronized tenures lead to voluntary exits that coincide.