"[Analysis] Where do Incense spawns pull from, and where should you drop them for rare spawns?"

#PokemonGO: Whelp, they've rolled out the new tracker just as my data collection was winding down, so this may not be useful anymore. But god damn I did this so I'm still posting it. There's probably something usable in here. I hope. Maybe. /quietsobbingMy sample size was supposed to be larger, but I have the new tracker now, so it can't be. Such sweet sorrow. Raw data: http://ift.tt/2bfjInA collected data from 17 incense and 102 individual spawns in an attempt to find out if it was really better to drop incense with an empty tracker. I recorded the tracker's claims at each spawn, whether or not that pokemon appeared on the tracker at the moment or at any time during the incense, and how many of the spawned pokemon I'd seen up to that point (ie, rarity). I also noted stuff like CP, spawn time, and biome. I was level 20 for the entire duration. Assumptions The time it took me to record Nearby pokemon after a spawn was not significant enough to effect the data. Ie, Nearby pokemon weren't changing so fast I couldn't reliably record them.The distribution of pidgey, rattata, and spearow was proportional across sampling areas. In the data set there is one lure that was dropped in a "Rural" area. I ultimately decided this assumption didn't hold true for that area and nixed it. But I'm pretty confident that in both the Urban and Suburban areas the liklihood of hypercommon spawns is relatively equal, just based on my own experience at home and at work.The data fits the conditions for the statistical tests I ran. You can find more about these by googling the tests.The data for incense used while stationary and used while moving would look roughly the same.Spawn frequency didn't suddenly change in the middle of testing. I have no reason to think it did, but who knows. Notes One data set, L2, had to be thrown out because I was called into a meeting and couldn't record the end of the incense. Alas.It was weirdly hard to keep the Nearby list low. Even when it started empty, it almost always had 6 or so by the end. This makes me sad I ended up throwing out the Rural data, but I just couldn't get enough of it to draw conclusions from.There's one Drowzee in L2 spawn whose CP is marked as "---". I took too long recording the Nearby and it despawned before I could see. Non-Statistical Observations Incense can spawn unseen pokemon. I am now the proud owner of a (shitty IV) snorlax and tentacruel. Thanks, incense!When stationary, you get six spawns from incense, one roughly every five minutes. Interestingly, I had one sample where I got seven. I have no idea why this happened -- I can only think it was a server-side glitch of some kind. Spawns reliably happened at 29, 24, 19, 14, 9, and 4 minutes.There was no time where a pokemon spawned with fewer than 3 minutes left. This might change if you're moving, but I'm not sure.Not bolding this because it's not particularly scientific, but it's still worth pointing out, I think: One of my Urban incense spawned a kingler while kingler was in the Nearby list. I'd never seen a wild kingler before. It's a sample size of 1, but it does make me wonder if you can use incense to attract rare spawns you'd otherwise have to hunt around for. Analysis Sample: 15 lures - 8 Urban, 7 Suburban, a total of 91 spawns Suburban incense were always set down with 3 or fewer mon in the Nearby list, and never had nine Urban incense was always set with 5 or more mon in the Nearby list, and had nine 76% of the time. Question 1: Is incense checking something other than the Nearby list? Basically, this is testing the idea that incense is filling its queue, so to speak, with first pokemon who are Nearby and second with any pokemon that can spawn in your area. If it wasn't checking the area, and only was going on the Nearby list, the amount of time a spawn would have appeared on Nearby wouldn't be drastically different regardless of the number or pokemon on Nearby.Urban incense spawned pokemon that never appeared in the Nearby list 24.5% of the time. Suburban incense spawned pokemon that never appeared in the Nearby list 85.7% of the time.A z-test for difference in proportions gives a Z-Score of -5.8319. The p-value is 0. The result is significant at p <0.01.This suggests pretty heavily that spawns can feed from somewhere other than Nearby. This isn't an exciting result -- and it's pretty obvious -- but it's necessary to establish. Question 2: What is the relative rarity of spawns when incense is pulling from the biome more than from Nearby? So if we establish that incense is pulling from two "pools" of spawns and that it's more likely to pull from the non-Nearby pool when the Nearby list is lower, we can try to test whether one pool is 'rarer' than the other. There are two big assumptions in play here: Relative distribution is the same. This is the big one, and my personal experience at my house and at work with non-incense and -lure spawns does back it up. It's the assumption that I'm equally likely to see a supercommon spawn like a rattata in Urban as I am in Suburban. I may see more overall in Urban since there are more spawns there overall, but the amount should be proportionate to the rate of uncommon spawns. Nests haven't significantly changed over the past month. I only saw two pokemon I'd never seen (ie, 'seen' in the Pokedex) before during this during the luring, and based on my own observations I do think this holds up. It's so hard to know. But I think being in a slightly out-of-the-way area helps me here, as I seriously doubt Boston suburbs are subject to the same constant reshuffle more major metros are. With two exceptions, all the pokemon I saw here were ones I wasn't surprised to see. (I did have a dratini nest at my office nerfed, but it seems to have been filled by the area's other spawns as opposed to something completely new.)During Urban incense, I saw 7 pokemon who I'd seen 10 times or fewer in the pokedex (14.3%). During Suburban, I saw 17 (40.5%). The Z-Score is -2.8265. The p-value is 0.00233. The result is significant at p <0.01.This is the more exciting result. It suggests that incense being dropped with three or fewer pokemon nearby was spawning more rare pokemon at a statistically significant rate.This suggests that dropping incense in more rural areas does in fact get you rarer spawns.Upping the "rarity" threshold to 20 or fewer prior encounters actually creates a more extreme result (16.3% vs 66.7%) -- The Z-Score is -4.8958 and the p-value is 0.In the other direction, if I look at spawns of pokemon I've seen more than 45 times -- Weedle, Zubat, Pidgey, Spearow, Drowzee, Rattata -- it's 69.4% vs. 19%, also significant at p <0.01.This surprised me because I play so much more at the area around my house than I do around my office, so I figure I've seen many more of the suburban biome mon than urban, but if that's true it didn't make a difference.This is also despite the fact that the mon that did appear in the suburban Nearby were still common -- pidgey, drowzee, spearow, rattata, etc. In fact, of the 152 Nearby pokemon I recorded in the suburban area, 29% were pidgey alone. Other Calculations I had some other data so I did some stuff for fun. The average CP of Urban spawns was 217.63. The average of suburban was 259.7. This is not a significant difference. (t = -1.133, p = 0.13)There was no significant difference between the average CP of the first spawn and the CP of the last spawn. That is, CP didn't rise as the incense went on. (t = 0.36, p = 0.64) tl;dr If you're trying to find pokemon that are uncommon in your area, drop an incense when there are few pokemon in your Nearby (now Sightings). My evidence suggests you're more likely to get rare spawns.You can find completely new pokemon with incense. I'm sure there's other stuff that can be done with the data (in particular, I was curious as to whether there was a correlation between the CP of the first spawn and the average CP of the incense) but I'm tired and a bit bummed that the new tracker rolled out just now.I hope this was worth something to someone!edit: I just wanted to thank everyone for all the comments! You're all too kind, and after a tough few weeks you've quite literally brought a tear to my eye -- I'm glad this weird little project was useful to anyone. via /r/TheSilphRoad http://ift.tt/2aSk5pb