Based on allegations from a few months ago.
NYT:
In its blog post on Thursday, U.S. News said that after learning of the criticism in March, it had asked Columbia to substantiate the data it had reported, including information about the number of instructional full-time and part-time faculty, the number of full-time faculty with the highest degree in their field, the student-faculty ratio, undergraduate class size and education expenditures.
“To date, Columbia has been unable to provide satisfactory responses to the information U.S. News requested,” the post said.
...
Columbia had originally defended its statistics, but said in a statement on Friday that it “takes seriously the questions raised about our data submission,” and that it would not submit further “undergraduate-related information” to U.S. News while its own investigation was underway.