By demanding higher salaries for teachers, unions give school districts a strong incentive to dismiss ineffective teachers before they get tenure. Highly unionized districts dismiss more bad teachers because it costs more to keep them. Using three different kinds of survey data from the National Center for Education Statistics, I confirmed that unionized districts dismiss more low-quality teachers than those with weak unions or no unions. Unionized districts also retain more high-quality teachers relative to district with weak unionism. No matter how and when I measured unionism I found that unions lowered teacher attrition. This is important because many studies have found that higher quality teachers have a greater chance of leaving the profession. Since unionized districts dismiss more bad teachers while keeping more good teachers, we should expect to observe higher teacher quality in highly unionized districts than less unionized districts – and this is exactly what I found. Highly unionized districts have more qualified teachers compared to districts with weak unionism.
Oddly enough, crappy wages–which happen to coincidence with the loss of union power–lower teacher quality:
Indiana, Idaho, Tennessee and Wisconsin all changed their laws in 2010-2011, dramatically restricting the collective bargaining power of public school teachers. After that, I was able to compare what happened in states where teachers’ bargaining rights were limited to states where there was no change. If you believe the argument that teachers unions protect bad teachers, we should have seen teacher quality rise in those states after the laws changed. Instead I found that the opposite happened. The new laws restricting bargaining rights in those four states reduced teacher salaries by about 9%. That’s a huge number. A 9% drop in teachers salaries is unheard of. Lower salaries mean that districts have less incentive to sort out better teachers, lowering the dismissal rate of underperforming teachers, which is what you saw happen in the those four states. Lower salaries also encouraged high-quality teachers to leave the teaching sector, which contributed to a decrease of teacher quality.
Most importantly, it’s good for the students:
Since there’s currently no data on student performance by school district levels with nationally representative samples, I use high school dropout rates as a measure of student achievement. My study found that unions reduce the dropout rates of districts. This is where my study differs from some earlier ones that found that unionism either had no impact or had a negative effect on the dropout rate. I define unionism more broadly than those earlier studies. It’s not just collective bargaining that matters, it’s the union density of teachers in a district that’s important. Union density measures the strength of the union, because even when teachers can’t engage in collective bargaining they can use their collective *voice* to influence the educational system. What I found was that union density significantly decreased the high school dropout rate, even in districts without collective bargaining agreements.
But teachers unions are the greatest evil known to mankind. Or something.
Also worth noting this study came out months ago. Oddly enough, it didn’t make the news…