The Detroit News reports that there are fewer opportunities for new teachers in Michigan’s public schools and the profession as a whole is getting older. Amazingly, even though the article cites a number of different education experts, no one mentions the most obvious reason for this phenomenon: union contracts.

Nearly all teachers union contracts dictate that when school districts need to downsize (very common in an era of declining enrollment and rising labor costs), the districts must use seniority as the sole factor in determining who gets laid off and who keeps their job. This works to automatically increase the average age of Michigan teachers.

Some union contracts go to great lengths to avoid using something other than seniority to determine layoffs. For instance, when there is a tie in seniority between two teachers eligible for layoffs, the Ann Arbor school district uses the last four digits of a teacher’s Social Security number to determine who goes and who stays. The lower number “wins.” Battle Creek uses the same method, but the teacher with the higher number wins.

Fortunately, these kinds of arbitrary layoff procedures may be coming to an end in Michigan. Statewide reforms were passed last year that prohibit school districts from making personnel decisions based solely on seniority. These reforms, however, would likely be overturned if the union-backed “Protect Our Jobs” constitutional amendment is approved in November.

Nevertheless, hopefully in the future, the teachers who remain in the profession won’t just be there because they have the most years on the job; they’ll be there because they’re the most successful at improving student learning.