A plagiarism complaint filed last month against Robin DiAngelo, the author of a number of books on racism including White Fragility, has now been dismissed.

The complaint – which cited 20 instances of alleged research misconduct in DiAngelo’s 2004 doctoral thesis – was lodged with the University of Washington, where the author completed her PhD and is now an affiliate associate professor of education.

In a letter dated 11 September and shared with the Guardian by DiAngelo’s US publisher Beacon Press, the university said that the complaint “falls short of a research misconduct allegation that would give rise to an inquiry”.

DiAngelo’s thesis, titled Whiteness in Racial Dialogue: A Discourse Analysis, uses the exact or slightly tweaked wordings of other scholars without quotation marks or proper referencing. DiAngelo listed these authors in a reference section, but in several cases she did not cite their names next to the relevant sections in the text of the thesis itself.

In its letter, the university said that the complaint does not identify “sufficiently specific and significant” evidence of plagiarism, defined by the institution to mean “the appropriation of another person’s ideas, processes, results or words without giving appropriate credit”.

The university went on to say that the examples given in the complaint do not amount to plagiarism because the institution’s rules allow for “the reuse of a moderate amount of language to describe a commonly used methodology, previous research or background information”.

The complaint was published by the Washington Free Beacon, a conservative news site that has published a number of similar complaints. Claudine Gay, Harvard’s first Black president, resigned in January after reports by the Washington Free Beacon highlighted instances of alleged plagiarism. In February, the site published a plagiarism complaint about a diversity, equity and inclusion (DEI) officer at Columbia, Alade McKen. In March, it published a similar complaint against the chief diversity officer of the University of Wisconsin-Madison, LaVar Charleston.

“Anti-DEI activists have been clear about their agenda to discredit DEI efforts, and claiming that progressive scholars who write about race have engaged in plagiarism is one of their more predictable strategies,” said DiAngelo in response to the complaint’s dismissal. “I am certainly not the first in the DEI field to be accused – progressive Black scholars in particular have been targeted with this allegation.”

Two members of the UK’s Quality Assurance Agency for Higher Education’s (QAA) academic integrity advisory group who reviewed the complaint last month told the Guardian they thought that plagiarism had taken place. Though “plagiarism accusations are often political, this does not mean they are unfounded”, said Stephen Gow, QAA advisory group member and a Leverhulme research fellow at Edinburgh Napier University.

DiAngelo, who is white, is best known for her book White Fragility: Why It’s So Hard for White People to Talk About Racism, which was published in 2019 in the UK. Her other books include Nice Racism: How Progressive White People Perpetuate Racial Harm, which was published in 2021 in the UK.

The University of Washington did not comment specifically on the case, citing confidentiality. “We are committed to the integrity of research conducted at the University of Washington,” it added.