A new study analyzing over 600,000 letters of recommendation by college counselors shows that letters written for students at private high schools were, on average, 20 percent longer than those for public school students. Their letters were also more likely to emphasize certain details known to appeal to colleges, such as intellectual promise and participation in extracurricular activities.

The study, which focused on recommendation letters for students who applied to at least one selective institution, was conducted by a team of researchers from several universities and the Common App—the undergraduate college admissions platform used by over 1,000 institutions—using Common App data. The researchers used advanced natural language processing technologies to analyze how students’ personal characteristics, as well as the type of high school they attended, correlated with the letters’ length and the frequency with which counselors wrote about certain common themes, such as good classroom behavior, achievement in certain academic areas or athletic prowess.

Julie J. Park, an admissions researcher and a professor of education at the University of Maryland, said the research team wanted to investigate how potential bias within the nonstandardized elements of college applications can impact college admissions outcomes. It’s a topic that hasn’t been interrogated with the same scrutiny as, say, standardized testing, in part because of the difficulty parsing large archives of letters without advanced technologies.

“We have these tools now that can sort of condense and synthesize and find patterns within these data sets of nonstandardized data, right?” she said. “With college admissions, this is really exciting because for a long time, we were more reliant on metrics that were already standardized—things like GPA, test scores, that were readily quantifiable—and we were very limited in our ability to study other parts of the application, like the essay, letters of recommendation and extracurricular activities.”

The research builds upon prior studies that show college counselors’ biases can influence low-income and Black and Hispanic students’ college choices. Low-income students of color, especially at urban schools, have reported feeling less supported by their college counselors than their peers. Research has also found that college counselors sometimes discourage low-income and Black students from pursuing admission to selective four-year colleges.

The researchers found disparities in the content of letters based on socioeconomic indicators, such as whether a student used a Common App fee waiver. Letters for first-generation students and fee-waiver recipients included significantly fewer sentences on intellectual promise, academics, STEM, extracurriculars, arts and athletics. That remained consistent even when comparing those with standardized test scores in the 95th percentile, and when comparing letters written by the same counselors.

The overall length of letters for fee-waiver recipients was relatively long—on par with private school students—but the space was used differently. Whereas private school students’ letter writers tended to use the space to highlight academic or extracurricular achievements, letters for fee-waiver recipients were more likely to include information about students’ “personal qualities.” That might mean that counselors used the majority of the space in their letters to describe how the student overcame economic disadvantages or other challenges, Park said.

“In some ways, there was a crowding-out effect,” said Park. “The letters are focusing on the personal qualities and the contextual circumstances, but they’re less likely to talk about other aspects of the student’s experience.”

Black and Hispanic students also received shorter letters of recommendation than white and Asian students, and their letters contained fewer sentences describing their intellectual promise. These disparities generally disappeared when comparing students with the top SAT and ACT scores, but even among those high-achieving students, the letters were less likely to mention extracurriculars, arts and athletics than their peers’.

That data lines up with previous research by Park and Brian Heseung Kim, Common App’s director of data science, research and analytics and another researcher on this project, on the extracurriculars listed by high schoolers on their college applications. They found that white and Asian students included more activities over all than Black and Hispanic students, and also characterized themselves as holding high-level positions or achieving significant success within more activities.

“Certain activities are affected by a legacy of historical exclusion. This exclusion, whether intentional or not, is often combined with community-based socialization that influences how certain activities become dominated by certain groups. For example, the competitive spelling bee circuit is frequented by many South Asian American students, and classical music is dominated by East Asian Americans and white students,” Park and Kim wrote in a Brookings Institute article about the research published in 2023. “Disparities may also be driven by socialization that white, Asian American, and higher-[socioeconomic status] students experience, where ‘résumé packing’ is a common behavior within peer groups.”

This research might call into question whether letters of recommendation are even a necessary part of the admissions process—something enrollment experts have been asking for years. Moving forward, Park said, if they do stick around, higher ed institutions might reconsider whether they need the traditional three recommendation letters. Adding a word limit, too, could help alleviate some of the disparities.

“Beyond the inequities that are affecting letters directly, there are a lot of other issues with letters, right? They add a lot of work for teachers and counselors, and how valuable the information is—you could probably talk to five people in admissions and hear five different answers,” she said.

“If you are going to keep letters, you need to be reading them with the context for opportunity in mind. That goes for lower-[socioeconomic status] students that traditionally have not had access to as many resources. That also means paying attention to the context for the other end of the spectrum—wealthier students, especially students from private schools, and the benefits and privileges that can come with going to a school that has a college counselor whose sole job is to write these beautiful letters.”