(Slobodan Vasic/iStock)

A weak economy appears to have at least one upside: Schools are able to hire more effective teachers, according to new research.

Teachers hired during recessions were significantly more effective, as judged by their students’ performance on standardized tests, than teachers hired during better economic times, according to working paper published this week by the National Bureau of Economic Research.

The paper provides the first direct evidence of what would seem to be common sense: The state of the overall job market affects the quality of new teachers. It was written by Harvard education professor Martin R. West and economists Markus Nagler of the University of Munich and Marc Piopiunik of the Ifo Institute for Economic Research in Munich.

So what does this mean for policy? It doesn’t make sense to rely on recessions to improve the teacher candidate pool. But the study suggests that school districts could attract higher-quality teachers by paying new teachers more. Or in the words of the authors: “Increasing the economic benefits of becoming a teacher may be an effective strategy to increase the quality of the teaching workforce.”

The research is based on an analysis of the “value-added measurement” scores of 33,000 fourth- and fifth-grade teachers in Florida. Value-added measurements, or VAMs, are the product of complex and controversial statistical formulas that attempt to figure out how much of a student’s learning can be attributed to her teacher.

(Teachers unions have criticized value-added measurements as arbitrary and unfair, and a growing number of groups, including the National Research Council, have cautioned against using value-added scores to make personnel decisions.)

Teachers who entered the profession during recessions were roughly one-tenth of a standard deviation more effective in raising students’ math test scores than teachers who entered the profession during better economic times. The recession effect was smaller in reading — about half as large.

Other factors — such as teachers’ age and race, and the characteristics of the schools they worked in — could not explain the differences that researchers found between teachers hired during recession vs. non-recession periods.