"Pokemon spawns may have "rarity tiers" like eggs, dependent on biome"

#PokemonGO: By now most of us have seen the recent TSR research group post about tiered hatch rates for Pokemon (http://ift.tt/2mWoaPr). The gist of it is this: each Pokemon available in an egg is assigned a tier, the Pokemon in each tier are assigned the same weight, and eggs are distributed accordingly -- that is, a Pokemon in the Common:Uncommon:Rare:Ultra-Rare tier will hatch at the rate 8:4:2:1 over the total sum. I'd like to suggest that spawn rates are determined analagously, with the tiers determined by biome, and spawns grouped together by evolutionary "family".First, some data. I’ve been tracking spawns at my local river biome, which has a distinct advantage in that spawn diversity is fairly low. Here’s a chart of the distribution of 1000 spawns tracked since after the Valentine’s Day event:http://ift.tt/2lSHxcr definitely isn’t an original idea, but it seems to me that spawn rates are based on evolution “families” rather than just individual species (with exceptions such as in the case of Eeveelutions, Dragonite, etc.) Each member of the family then constitutes some percentage of familiar spawns, with first forms being the highest, but these proportions differ across families (for example, Octillery constitutes about one third of Remoraid family spawns, while only 2/156 Psyduck family spawns were Golduck). If we group the data this way, something interesting happens:http://ift.tt/2nkO8cE spawn rates look to be tiered, similarly to egg hatches. In the spirit of the hatch rates, I’ll divide the families into a few groups:Abundant (weight 50): Goldeen, Psyduck, Poliwag, Magikarp, StaryuVery Common (weight 24): Slowpoke, Remoraid, ChinchouCommon (weight 8): SquirtleRare (weight 4): Tentacool, Dratini, MantineVery Rare (weight 1): Krabby, Qwilfish, Spinarak, Marill, perhaps others like Horsea and Shellder which didn’t appear in this data set but have been spotted here previously should be here as wellThis would give spawn rates of 50/346 = 14.4% to Abundant families, 6.9% to Very Common families, and so on, down to 1.2% for Dratini/Dragonair and a quarter of that for the least common families.http://ift.tt/2lSwJuR course, this model has only been tested on this (fairly small) data set in this one biome, and, if we’re willing to make the numbers crazy enough and allow enough tiers, we can always alter this model to fit any data set, but I have a suspicion that this is how spawn rates are determined. The numbers for the different tiers could of course be different from mine (a preliminary look at other data sets makes me believe there’s probably a weight 12 group as well) but this type of model makes sense for the following reasons:It’s easy to code. Choosing a spawn rate for every Pokemon in every biome? No thanks. It’s way easier to tag Pokemon as having a rarity class and converting that to a spawn percentage for the RNG.It’s easy to change. Instead of mucking with percentages and making sure the sum is 100, if Niantic wants to make a Pokemon more common, they can just move it into a more common tier. During the Valentine’s Day event, Niantic probably just moved all of the pink Pokemon up a few tiers in each location, or just applied some kind of multiplier to the weights for these Pokemon.It explains how nests work. Every migration, a nesting Pokemon is (randomly) chosen for each nest location. At those locations, it would enter (probably) the most common spawn tier for the duration of the migration. Pretty simple. It also explains why nests appear to “skip” some migrations. It doesn’t skip at all; it’s just that the chosen Pokemon was already in the tier for nest spawns, and so there’s no observable change.Some potential sticking points:A thousand data points is simply not enough to make these ratios clear. The numbers I’ve listed seem plausible, but it would be even harder to test this in any biome that has a greater diversity of spawns, which is to say pretty much everywhere else.What about the day/night spawn rate change idea? Maybe some Pokemon move up or down a tier depending on the time of day.I encourage everyone who has lots of data on individual spawn points to see if this idea fits their observations, and I encourage everyone else to start keeping track! If we can somehow confirm this, we’d be that much closer to understanding and classifying biomes.tl;dr: I have reason to believe that Pokemon families spawn according to an assigned biome-based rarity classes, which makes sense in light of nest and event mechanics but would take lots of data at many individual spawn points to confirm or refute. via /r/TheSilphRoad http://ift.tt/2mBVuKs