I was wondering the same. In https://arxiv.org/pdf/1304.1067.pdf https://arxiv.org/pdf/1304.1067.pdf they say "chosen according to some criteria like academic a

I was wondering the same. In https://arxiv.org/pdf/1304.1067.pdf https://arxiv.org/pdf/1304.1067.pdf they say "chosen according to some criteria like academic appointment status or recent research productivity".