The analysis of shiny rates during the Ingress Day left me deeply unsatisfied. Allowing for a small amount of systematic bias and error in the data gathering we find a pattern in the numbers used for boosted shiny rates by Niantic:
| Shiny Rate | Occurrence | When |
| 1 in 10 (or close) | Recent 3 hour raid events Moltres, Zapdos, Ho-Oh, Gengar (and several more since) | Legendary and non-legendary raid events (apart of Articuno) |
| 1 in 20 (or close) | Articuno raid event, Lugia, Kyogre, Ho-OH normal raids | Legendary raids before events and Articuno event |
| 1 in 25 (or close) | All community days, Pinsir, Beldum, Wingull (and several more since) | Limited time global introduction of new boosted Pokémon |
| 1 in 50 (or close) | Baby Eggs, Mawile and Absol, Aerodactyl and Pineco | Quest, Eggs, Raids, Wild boost in combination with Quest/Raid |
| 1 in 450 (or close to 500) | Everything else | Unboosted rate / default |
You can read more about the rates that are published on the SilphRoad Research pages. If we allow 500 instead of 450 then all values are factors of 1000. Actually the factors of 500 is also proposed in Part 3 https://thesilphroad.com/science/shiny-egg-hatches-field-research-encounter-rates/ but this is the wrong place to discuss the merits of 1 in 450 and 1 in 500.
All the past shiny rates leave Cubone and Ponyta rates of 1 in 120 and 1 in 160 which stick out like sore thumbs if you believe that Niantic keeps it simple. And it just makes no sense at all to introduce 2 different Pokémon on the same day but assign them different rates.
And such strange shiny rates never repeated themselves So there is a good chance something pretty different happened.