Though everyone typically sees unions as being mainly for the benefit of their members, teachers' unions use a lot of pro-student rhetoric and often come across fairly angelic. They probably do have only the kids' interests at mind, but a new paper suggests that their existence doesn't necessarily benefit those kids.

Data comparing students' outcomes to teacher unionisation has until recently been fairly lacking. But according to the new study published last month, duty-to-bargain laws (which mean employers need to work with unions) lead to significantly worse labour market outcomes for students in schools subject to them.

Previous research has shown us that teacher collective bargaining laws increase teacher union membership and increase the likelihood that a school district unionises for the purpose of collective bargaining—i.e. they achieve their direct goals. But looking into the effect on the kids has been hampered by a lack of information liking people’s outcomes and the time that duty-to-bargain laws were passed.

This new study, conducted in the US by Michael F. Lovenheim and Alexander Willen, takes the timing of the passing of the duty-to-bargain laws between 1969 and 1987 and links them with long run educational and labour market outcomes among 35-49 year olds in 2005-2012, i.e. those subject to them..

What they found was that men subject to increased unionisation work less hours as adults and earn less. There is also evidence of a small decline in educational attainment for men and a long-run negative effect on labour supply for women that is equal in magnitude to that of men.

Of course, some of the kids tin this paper were subject to a vastly different educational environment than exists today, so we can't necessarily extrapolate to the UK. Nonetheless the general finding is quite plausible, and should contribute to policy debates around increasing or reducing the role of collective bargaining in the education sector.

If future research in this field continues to make the negative relationship apparent, we may be ever closer to exposing how teaching unions lower educational standards by supporting the timeservers over the strivers in the teaching profession.