Or not. Link
A recent academic paper by economists Michael Lovenheim and Alexander Willén argues that men who lived as school-age children in states where teachers were allowed to bargain collectively are less likely to work as adults and, when they do work, they earn significantly less than men who grew up in states where teachers were not allowed to bargain collectively.
There are at least three reasons to be deeply skeptical of their findings.
First, the chain of causal links is extremely circuitous. The reasoning runs from a student's initial potential "exposure" to teachers' right to collective bargaining all the way through to the conclusion that this "exposure" significantly worsened labor market outcomes decades later as an adult. In most of their analysis, the authors rely on data that let them know the state where a person was born and the employment situation of that same person in a single year between the ages of 35 and 49. The researchers use this information to construct a simulated educational history for each adult, where they assume that the person attended K-12 school in the state where they were born. The researchers, however, don't actually know that an individual lived in the state of birth while at school age, or whether the school the individual attended was unionized, or even whether the individual attended a public or private school.
I think it's a stretch to call these guys "researchers". They couldn't be bothered to actually research the thing their entire argument hinges on - what state these men lived in while they were school-aged. Who let them publish this in the first place? Next, they'll be submitting academic papers with "research" that involves reading an encyclopedia entry.