Your metric will lock me out:I did Real and Complex Analysis sophomore year but was forced to take intro to statistics senior year in order to graduate.
That kind of thing is in every transcript. Doesn't look strange at all with the odd one like that. It's rather systematic failure I'm trying to look out for.
The usual sign is someone e.g getting a masters degree 2000-2005, and passing the introductory math classes in 2005.