Many schools around the country are struggling to find enough teachers. Large numbers of teachers quit after a short time on the job, so schools are constantly struggling to replace them. The problem is particularly acute at rural schools and urban schools. The most common level of experience of teachers in the United States now is one year on the job.

At the same time, enrollment in teacher training programs at colleges and universities is plummeting, and schools are looking to other sources to fill classrooms.

In Nevada, a desperate need for teachers this year led to allowing people with just a high school diploma to fill in as substitutes. Oklahoma recently changed its law to allow people with a bachelor’s degree — in anything — to teach indefinitely on emergency teaching certificates. Schools in Texas are increasingly turning to for-profit teacher training programs.

Data we obtained shows that nearly one in four of the teachers hired in Texas last year came through a single for-profit online program — one that’s now making its way into other states. We’ll look at the implications of these changes, both for children and for the teaching force.

Read more: Texas company fuels rise of for-profit teacher training programs