Over the last few years, there has been a surge in challenges to books in public school libraries. These “banning” battles have drawn considerable attention – and alarm – but they miss deeper questions: How do public schools select books in the first place, and do they offer a balance of opinions on controversial issues?

Findings in a Cato Policy Analysis released today, “Are Public School Libraries Accomplishing Their Mission?” suggest that public schools do not tend to stock a balance of views, but lean, perhaps strongly, to the left.

To test whether public school libraries carry balanced viewpoints, we randomly selected 200 “regular” public school districts (no charter schools or special districts) and looked for eleven titles in libraries serving middle and high schools. We selected books seeking a balance of views on race and the fundamental nature of American society.

Basically, is the country grounded in liberty and equality, or has it always suffered from systemic racism?

As the figure above shows, we were far more likely to find titles that suggest the country suffers from systemic racism – books in the Stamped series by Ibram X. Kendi, and Ta‐​Nehisi Coates’s Between the World and Me – than books that take issue with the thrust of Kendi’s and Coates’s arguments, or that present the United States as fundamentally good.

The titles directly addressing the kinds of arguments put forth by Kendi and Coates are Woke Racism by John McWhorter and Cynical Theories by Helen Pluckrose and James Lindsay. Books in the Rush Revere series by Rush Limbaugh represent the view that the United States is fundamentally good.

Far more schools had libraries that made the Kendi and Coates books available than the others. Especially stark was that almost 40 percent of schools with searchable libraries – 135 total – had access to Stamped: Racism, Antiracism, and You, but less than 1 percent had access to Woke Racism or Cynical Theories. Each of those conservative books was found in just one school.

And as seen in the next figure, when we broke districts down by the 2020 presidential election winner in their county, schools in Trump‐​won counties were much more likely to stock at least one Rush Revere title than in Biden‐​won areas. But more schools in Trump‐​won counties held Stamped: Racism, Antiracism, and You, and Between the World and Me than held a Rush Revere book.

These findings suggest that public school libraries have a yawning left‐​leaning bias in acquiring books. As the paper lays out, this is consistent with substantial evidence that the library profession has a pronounced liberal lean.

This seems to be assumed within the profession, and librarians who donate to Democrats outnumber those who give to Republicans roughly 9 to 1.

It also appears that publications on which librarians draw to assess what books to stock, such as School Library Journal and Kirkus Reviews, have liberal biases. They were more likely to have reviewed the liberal books on our list than the conservative books, and to have done so favorably. So not only might librarians favor liberal views, they also draw on recommendations from sources with their own liberal filters.

Is it, then, case closed that liberal bias among librarians and their preferred reviewers has created unbalanced inventories? No. The paper discusses other, very plausible explanations for some or all of the imbalance we found.

Based on our sample of books, it appears that conservative authors might not target public school libraries as aggressively as liberal writers. In particular, Stamped: Racism, Antiracism, and You has been heavily marketed to schools, including through a giveaway by the publisher in 2021. The Rush Revere titles have been significantly marketed, especially on Limbaugh’s own site, but that appears to have been more toward families directly than schools.

And Woke Racism – which is written in a clear way most high schoolers could likely follow – does not appear to have had any special outreach to schools. Nor has Cynical Theories, though it might be more complex than would be read by most high schoolers.

Another possible explanation for our findings that undermines the librarian‐​bias conclusion is that our list might not have included some balancing conservative books. We simply might not have thought of them. In addition, most public school book conflicts have been about fiction, often for kids younger than middle school. We did not examine fiction (Rush Revere is probably best described as historical fiction) and we focused more on older students. Our results, then, tell us little about book selection in the more commonly disputed areas.

As we were working on this paper, Columbia University professor Kirsten Slungaard Mumma released a much broader analysis of public school library holdings than ours, which suggests that school libraries tend to reflect the political makeup of their district populations. It included possible evidence of an overall left‐​leaning bias, though that was not a focus of her research. She also noted what motivated our paper: There is almost no research on public school library holdings and what leads to them.

If there is one clear conclusion about public school libraries, it is that they need to be studied more closely. Our paper, which includes not only the findings of our balance analysis but an overview of what researchers know about how these libraries work, is a step in that direction.