There were hundreds of reader comments on Education Week’s Facebook page this week about Cara Jackson’s previous guest post, What Does It Mean to ‘Overspend’ on Teacher Salaries?

Here, she responds to some of them....

Reading the Research on Teacher Salaries

Cara Jackson is a senior associate at Abt Associates, where she works on systematic reviews of research evidence and conducts program evaluations.

In the last post, I discussed research that higher teacher salaries are related to higher teacher retention, better teacher qualifications, and student achievement. We might see this relationship for a couple of reasons. First, more-experienced teachers tend to earn higher salaries and are on average more effective than less-experienced teachers. Second, higher teacher salaries could attract a larger and more highly qualified pool of applicants.

On Facebook, some people suggested that these findings could simply be a case of correlation, not causation. That is, students from families with higher socioeconomic status tend to do better on standardized tests, and teachers who work in wealthier school districts might earn more.

If the researchers had not considered factors such as student socioeconomic status, we might be concerned that teacher salaries are only related to better educational outcomes because of the wealth of the students and their families. But each of the studies cited did account for socioeconomic status.

For example, the author of the study using Schools and Staffing Survey data controlled for the median household income in the community, in addition to other factors that might affect a school district’s ability to hire teachers. Median household income helps capture differences in parental education, enrichment activities, community resources, student motivation, and student challenges. In addition, median household income helps account for potential teacher sorting. That is, teachers from more selective colleges might marry a college classmate, settle in a more affluent area, and then teach in their (wealthy) neighborhood school district.

The Michigan study and one of the North Carolina studies also used median income. In addition, those studies included median education in the analyses. The Washington state study took a similar approach, using the poverty level of the district and county unemployment rate.

Other studies used student data. For example, the studies from Florida and Denver included the percentage of free and reduced-price eligible students in their analyses.

Two of the studies used samples of similar schools or teachers. One of the North Carolina studies selected schools using free and reduced-price lunch rates. In the Tennessee study, the sample consists entirely of a subset of low-performing schools.

The more recent study using national representative data included a number of factors in the analysis: percent of students enrolled in free or reduced-price lunch programs, percent of children in poverty, percent of adults with a bachelor’s degree and above, percent unemployed, and median household income.

Every study cited considered the possibility that socioeconomic status might explain why higher teacher salaries are related to outcomes. Every study took steps to address this concern.

Other commenters chimed in to point out that extra duties might influence teacher and student outcomes as well. I agree and would add that we know that teachers’ working conditions matter for educational outcomes. Teachers working in supportive professional environments improve more over time than teachers working in less supportive contexts. Teacher salaries are just one of many ways we can improve educational outcomes.

Thanks again, Cara!