HMM: Arizona says you can start teaching before you earn a degree.

Public schools in the state have struggled to fill teaching vacancies for years, he writes. One survey found 26 percent of jobs are not filled by a certified teacher.

Would 19-year-olds be learning to teach on the job? I suspect districts that use the flexibility will be hiring aides as classroom teachers while they move toward a bachelor’s degree. Many districts have programs to help aides, who tend to be “diverse,” become teachers, but it takes a long time for someone working full-time to complete college.

Some Arizona districts are experimenting with team teaching. Arizona State’s Next Education Workforce initiative is working with schools to create teaching teams that combine veterans and novices.

How about pulling in more — many more — private-sector retirees with real-world experience and knowledge?