The Namerology Unisex Name Map is based on Social Security Administration counts of names given to babies born in 2018. Names were considered unisex if they appeared in the national statistics for both boys and girls in 2018, with a usage ratio of no greater than 4:1 in either direction. The unisex naming rate for a given state represents the percentage of babies in that state receiving a name from the national unisex list.
Note that the SSA state-specific lists only report on names given to five or more girls or boys in that state in a single year. The number of names reaching the five-baby threshold can vary enormously based on state population size. For instance, the SSA name data for California in 2018 covers 2,837 different boys’ names; the data for Wyoming just 139 different boys’ names. The results for very small states are thus less robust, and may undercount their actual unisex name rates since new names and creative spellings abound in the “long tail” of less common names.