Silph Study: #001


The Attack IV Correlation with Pokedex # has Disappeared

An anecdotal correlation between wild Pokedex # and attack IV (Individual Value) was oft cited in the first few months of the game. The effect of this was said to be:

  1. Low Pokedex #'d species (like Charmander, Squirtle, etc) were nearly impossible to encounter in the wild with high attack IV values
  2. High Pokedex #'d species (like Eevee, Snorlax, and Dratini) were almost always found with perfect or near-perfect attack IV values.

    On September 22nd at roughly 8:30pm EDT reports began trailing in that wild encounters had begun breaking this trend en masse. The Silph Research group assembled a crew of Researchers to gather data and test if the correlation still held. Before Sept. 22nd, the distribution of attack IVs had been observed by the community to follow this general trend:

    Within a few hours, the Silph Research group had recorded the IVs of 341 wild-caught Pokemon. Because there can often be multiple potential IV values, our dataset recorded the lowest possible attack IV based on known information about that Pokemon.

    The results were clear:

    Both "nesting" and non-nest Pokemon were tested and: the correlation was not found to be in effect anymore. This server-side change roughly coincided with the rollout of Android version 0.39.


    The findings from /u/NewSchoolBoxer were originally shared on July 23, 2016. Because /u/NewSchoolBoxer did not share the raw dataset, the Silph Research group is unable to find the historical coefficient of correlation for the July 23 dataset.

    In the period between July 23 and Sept 22, multiple reports were shared on the subreddit showing varying degrees of correlation. Because of this, we have suspicions that the attack IV's correlation with Pokedex # underwent multiple smaller changes in the two months between these data samples.

    This analysis does not attempt compare statistics between individual species, thus we do not need a sample size of statistical significance for each individual species. Rather, we are testing the correlation between the Pokedex # and the attack IV. The Coefficient of Correlation of the Silph Research Group's dataset was found to be 0.0074, which statistically means the correlation between Pokedex # and attack IV is extremely weak.


    This finding was shared on our subreddit on Sept. 23, 2016.