Here’s the link to the methodology for the USNWR social mobility ranking:
https://www.usnews.com/education/best-colleges/articles/how-us-news-calculated-the-rankings
Is that where your numbers come from?
All it measures is the 6 year graduation rate of Pell Grant recipients. It fiddles with the number a bit, comparing it to non-Pell Grant recipients and giving a boost to those school with larger percentages of Pell Grant recipients in their student body.
So it seems to be duplicative of the evaluation in this thread – that the elites don’t seem to get the lower SES kids in the door. They opt for state schools instead. I don’t think you can conclude that it is on purpose just from that. Or, I don’t know how this works, honestly, if the kid gets a full ride at Harvard, do they even bother getting Pell Grants? That would skew the data.