(No sleight intended against Captains but statistically just a fact of life).
Quote "There are lies, damned lies, and Statistics." ( Disraeli ? )
I would say that 'statistically' a Captain would do the flying when an approach was considered more demanding, i.e. a non-precision one, why stick your neck out and give it to a F/O whose skills one might not have had personal experience of, so if 'statistically' more Captains fly NPA's then 'statistically' most of the NPA accidents would happen when a Captain was flying.
QED