I am not sure how one would go about statistically comparing AP and IB because the programs are different, AP is a la carte and IB has the diploma sequence. Are they comparing IB diploma registrants vs. anyone who has taken an AP course? Realize that only the top students will register for the IB diploma sequence.
@bopper - The AP course sequence can also result in 32 credits at Bing, it is not specific to IB.