"How Size is Determined in Pokemon Go (plus youngster/fisherman medal)"

#PokemonGO: In a recent evolution session, I evolved 73 weedles and noted every single piece of data I could find, hoping to see if I can find something to predict post-evolution quick moves. I have no conclusive results from that yet but figured out somewhat how size is determined.To begin, here are the base weights and heights from the pokedex:PokemonHeightWeightWeedle0.3 m3.2 kgKakuna0.6 m10 kgRatio23.125When dividing a kakuna's weight by its weight as a weedle, I always get very close to 3.125 (exact range is 3.095 to 3.130). Similar for height (1.96 to 2.226). This leads me to predict that these are based on an underlying IV that remains constant. However, the range difference is not explained by rounding which I tested by adding or subtracting 0.01 and recalculating. Thus, size is NOT randomly regenerated when a pokemon is evolved.The next thing I examined is how the indicators of size are determined. Since the kakuna and weedle data is autocorrelated, I used only the weedle data for this analysis. I calculated 3 ratios:Height Ratio = Height/base_height Weight Ratio = Weight/base_weight Size Ratio = Weight Ratio + Height Ratio Based on this, I have found that the indicators for XS and XL will be shown on your pokemon page if your respective height or weight ratio is as follows:SizeRangeXS<0.75XL>1.25For overall size, your appraisal will be based on your size ratio:SizeRangeXS<1.5Small1.5 to 1.75Large2.25 to 2.5XL>2.5I then calculated the correlations between height and weight and the standard deviations for them. I find that height and weight are highly correlated (p<0.00001). I also found that the standard deviation for weight is significantly larger than height (0.118 and 0.283 respectively) which is why we see XS and XL weight more often than XS and XL height. My standard deviation for size ratio is 0.382. This means that the distributions are not independent and normal. Possibly, one random number is used to determine height ratio and an additional random number is added to the formula to determine weight ratio. Additional TestsI then went through my entire pokemon bag and verified that the cutoffs for determining XS and XL match as expected to make sure that this generalizes to all species. I also built a contingency table (Columns represent weight, rows represent height and verified that this is not statistically different from the probabilities from my weedle data:.XSNormalXLTotalXS92011Normal6420428316XL001010Total7320658337I then went to my medals and looked up my numbers for fisherman (24/174) and youngster (10/145). Most sites say that these are based on weight but people have found anomalies. I used my sizes based on the appraisal of my weedles and the weights from the contingency table to perform Fisher tests. My ratios for both medals are statistically different than the ratios based on weight but not statistically different from ratios based on appraisal size.To see if height, weight and size ratios were correlated with any other observable characteristics, I performed backwards stepwise regression against everything else you can get see or calculate from the front page such as CP, moveset (dummy coded), IVs, Lvl, perfection %. Other than CPM which was significant for weight ratio and size ratio, nothing else was related (this is likely a statistical anomaly unless it can be replicated). I performed a t-test of size variables before and after the IV scaling bug fix and found no differences. About the dataI am still cleaning up the data and will be happy to share it later since I know other people are looking at explaining post evolution moveset. 3 pokemon were hatched but all others were caught in Hong Kong. My weedle's weights were higher than normal (two tailed T-test p value is 0.0125) but heights were not statistically different than normal. TL;DR Youngster is based on XS rattata as appraised and fisherman is based on XL magikarp as appraised. These values are calculated from but different than weight and height. Pokemon also generally remain the same height and weight relative to others of their species after evolving. edit My conclusions for youngster and fisherman are based on statistical rather than experimental evidence. It is entirely possible that the cutoffs for these are not the same as the cutoffs for XS and XL in the appraisal system. If someone can figure out the exact cutoff points by catching a couple hundred of these (whether they are based off weight or size), that would be great. via /r/TheSilphRoad http://ift.tt/2dQ5rll