Is a good elementary teacher good in all subjects?

In most elementary schools, teachers are responsible for several subjects. Various personnel policies, such as evaluating teachers based on value-added estimates aggregated across subjects or departmentalizing teachers, implicitly make assumptions about how closely teacher effectiveness is aligned across subjects.

This paper
reports on research exploring these issues using student–teacher linked data from North Carolina to assess the correlation of teacher productivity across math and reading.

The authors find that assigning teachers to teach particular subjects based on their measured productivity could yield modest student achievement benefits.