Katir progression
3000m:
2015 - 8:48.27 - 17
2016 - 8:31.67 - 18
2018 - 7:56.62 - 20
2019 - 7:53.81 - 21
2020 - 7:44.13 - 22
2021 - 7:27.64 - 23
2022 - 7:35.73 - 24
2023 - 7:24.68 - 25
Katir's progression somewhat mirrors Grant's up until 2019. Then he improves an average of 8 seconds per year for 3 straight years. He regresses in 2022 (presumably due to injury/niggles) then takes a massive leap in 2023. That's when the alarm bells should have gone off.
Something to keep in mind is when you're operating closer to absolute human limits of performance, it's not a linear improvement curve, it's exponential. It's exponentially more difficult each second below 7:30. So even those 3 seconds of improvement between his 2021 and 2023 is damn near impossible. You'd have better luck getting 40% gains on the S&P year-over-year for 10 straight years.
With that said though, do I think Grant is a 7:25 guy clean? Questionable.
Grant Fisher 3k progression:
2013 - 8:32.65 - 16
2016 - 7:50.06 - 19
2018 - 7:48.56 - 21
2019 - 7:42.62 - 22
2020 - 7:39.99 - 23
2021 - 7:37.21 - 24
2022 - 7:28.48 - 25
2023 - 7:25.47 - 26