Tests and Stress Bias

A new study suggests that changes in levels of cortisol, a hormone associated with stress, during weeks of standardized testing hurt how students in one New Orleans charter school network performed — and kids coming from more stressful neighborhoods, with lower incomes and more incidents of violence, were most affected.

Published in a recent working paper from the National Bureau of Economic Research, the first-of-its-kind study contributes to conversations about chronic stress and testing, and helps clarify where those conversations intersect, indicating that one reason that family income tends to correlate with test scores may be because stress — both from the test and home environments — affects scores.

The Findings

The researchers — Jennifer Heissel of the Naval Postgraduate School, Emma Adam and David Figlio of Northwestern, and Jennifer Doleac and Jonathan Meer of Texas A&M University — measured the stress-levels of children at the New Orleans charter school network, comparing the cortisol in their spit during weeks with high-stakes standardized tests — those that have implications for course placement, school sanctions or rewards, or education policy — and weeks without testing.

What they found is that, on average, students had 15 percent more cortisol in their systems the homeroom period before a standardized test than on days with no high-stakes testing. Students who showed the largest variations in cortisol between testing and non-testing weeks tended to perform worse on tests than expected given their classwork and performance on non-high-stakes tests, among other measures. Cortisol spikes weren’t the only culprit; some students’ cortisol dropped on testing days, which was also associated with lower performance.

“The decreases in cortisol is more a sign that your body is facing an overwhelming task and your body does not want to engage with the test,” Heissel says.

Students from the most disadvantaged neighborhoods, with both the highest rate of poverty and crime, saw the largest changes in cortisol in advance of testing, suggesting that their scores were the most affected — and therefore the least valid measures of what they actually knew.

Boys also tended to see more variation in cortisol, supporting pre-existing research that boys get more stressed about achievement-related texts, while girls are often more affected by social pressures.

Stress Bias?

More research needs to be done, Heissel warns. This study only included 93 students across three schools in New Orleans. Nearly all of the students were black and from low-income families, although there was variation in the violence and level of poverty in their neighborhoods. Future research would benefit from larger, more diverse samples, although, Heissel notes, it’s hard to find schools willing to let researchers visit during testing weeks.

It also raises questions about how to temper the effects of cortisol variation on testing day. “How can we reduce that stress response? There are lots of questions raised by this research and I hope other people pick up the baton,” Heissel says.

But considering the importance of and frequency of high-stakes testing, the need for that research is urgent for anyone who interprets and makes decisions based off of test scores.

 “It calls into question what we’re really measuring,” Heissel says.