Martin Lee Allen: a whole law firm or just one person's name? I bring you a data-driven answer to this question.
Based on the 1990 U.S. census data, here is a list of names that are equally common as first names and last names:
|Name||Total Popularity (%)||Popularity as First (%)||Popularity as Last (%)||Closeness (%)|
I wanted a way to decide if a name was equally common as a first or last name. I decided to
use the formula
min(first / last, last / first), which I'm calling "closeness." It
probably has at least one other name, if not more.
I wanted to filter out all names with closeness <
c. First I binned the names by
closeness. Within each bin, I hid the first and last popularity and guessed whether that
name was predominantly a first name or a last name. I could guess accurately below
0.75 but not above it, so I set
c to 0.75.
Finally, I ranked all qualifying names by total popularity. The total popularity figure that I'm using is actually just the sum of the name's popularity as a first name and as a last name. This will be a slight overestimate since it doesn't account for people whose first names are the same as their last names ("Martin Martin?"). This is probably not a big deal.