The boring reason is that the Economist magazine
would (narrowly) plump for Ms Yellen
The word "narrowly" appears to have been imposed by a late-intervening editor, because the article’s case for Summers peters out after the words “cleverer”, “bolder” and “bravura public performances”.
The funny reason is that, per Bloomberg,
Among the achievements [Summers’ defenders] cite during his five years as president [of Harvard] are expanding financial aid, recruiting top academics such as historian Niall Ferguson
It strikes me that
Summers being over-impressed by Ferguson
is analogous to
Obama being over-impressed by Summers.
Ferguson has proven better than anybody in recent years one of the most important arguments against Summers, which is that
skill in one niche, combined with self-confidence,
correlates (if at all) negatively with competence in other niches.
A key difference is that there is only one Fed Chief, whose mistakes, whether of substance or tone, have particularly grave consequences.