Somewhere between 10 and 30 percent of all new teachers are hired after the school year begins. These late hires come in with lower college GPAs, are less likely to have prior teaching experience, and are less likely to be licensed in the area they’ll be asked to teach. Late hires tend to be concentrated in certain low-performing schools. And, since they tend to have higher turnover rates, late hires also contribute to higher churn in those schools.