It's been 30 years since states first began experimenting with alternative certification (AC) pathways for teachers, and while these routes have become firmly entrenched in many districts' talent strategies, the debate over their value continues.

In a recent study in the American Educational Research Journal, Christopher Redding and Thomas M. Smith contribute some new evidence around two long contended points—namely, whether alternatively certified teachers are prepared for the classroom and whether they're likely to stick around.

Preparedness. Previous research has established that there is no clear answer to the question of whether teachers from AC routes are better prepared or more effective than their traditionally certified peers. As our own review of non-traditional teacher prep shows, there are some high-quality alternative preparers of teachers, and there are just as many, if not more, ineffective alternative preparation options.

Analyzing data from the government's Schools and Staffing Survey, Redding and Smith turn up an interesting new finding on trends in AC. In the 1999-2000 school year, 23 percent of alternatively certified teachers entered the profession with no practice teaching, compared to 8 percent of teachers entering from a traditional prep program. By 2011-2012, the proportion of AC teachers with no teaching experience had grown to 40 percent. Why? 

Retention. If you ask most people about the problems with alternative routes, the number-one gripe is usually that AC teachers leave the profession more quickly than traditional candidates. Redding and Smith show that this is the case, but that it wasn't always so. In the 1999-2000 school year, there was little difference in the retention rates between early career AC and traditionally prepared teachers. By 2007-2008, however, the predicted turnover rate for AC teachers was 10 percentage points higher than that of traditionally trained candidates, even when controlling for school environment.  

Redding and Smith's work serves as another reminder that the quality of alternative certification programs matters—which is something we've been saying for a long time. Moreover, we'd do well to remember that most alternative certification programs are expensive to districts, candidates, and communities alike. With around a quarter of early career teachers now entering through AC pathways, the need to measure the returns on this investment is greater than ever.