There are 3 other threads on the half marathon in Valencia but none praising Jepksogei solely for her run. She ran 1:04:51 to break her old WR by 1 second.
Just as in her first world record (her 1:04:52 half in Prague) she went out crazy fast. (1:03:36 pace at 10k). She was paced by Ezekiel Kemboi and actually was 22 seconds slower today than in Prague but that helped her hang on at the end to get the record.
Her 2017 World Bests
April Prague 1:04:52 Half
and set 20k: 61:25
records en route.
September 10k WR: 29:43
5k record en route: 14:33
With better pacing what do you think she could run?
For those of you wondering how she's done on the track, Jepksogei ran the Kenyan champs and was 57 seconds behind Alice Aprot running 32:47, so she must not like the track at all or run that well at altitude.