NCTQ (National Council on Teacher Quality):

Our nation has open teaching positions that need to be filled by trained teachers. This is not a new national crisis but rather one America has been living with for years due to our unwillingness to adopt more strategic pay approaches. With rare exceptions, states have also shown no interest in limiting the number of teacher candidates their institutions can accept in some teaching fields to bring down the numbers nor in encouraging candidates to consider other teaching areas in shorter supply.

Teacher shortages are largely a product of local conditions, requiring local solutions. For example, until the state of Oklahoma pays its teachers more, it will struggle to fill positions, but solving its problem does not require us to raise teacher pay everywhere. Detroit suffers because its schools are so challenging. No solution will solve its problem until we address these local environments. The teaching field does not need solutions that set us back, like lowering teacher standards, hiring long-term substitutes and handing out emergency teacher certifications. There has been a mad rush by states to adopt these sorts of solutions. Instead, to fully understand the nature of teacher supply and demand trends, it is incumbent upon the nation, states, and school districts to collect better data and put these data into an historical context. States and districts should be able to identify the number of new teachers trained in each subject, how many graduate and do not end up teaching (because we know that nationwide, 50 percent of candidates do not end up in teaching jobs), where candidates apply for jobs, how many vacancies are open in each subject, and where these vacancies are located. In the absence of strong data systems that can pinpoint the broken points along the teacher pipeline, states and districts will continue to look for band-aids without resolving the underlying problems and the very real shortages which are not new but have gone on now for decades.

NCTQ Questions Teacher Shortage Narrative, Release Facts to Set the Record Straight.