I consider here registration associated with the legislatively enabled pre-registration of highschool age students, expressed as registration on 2019-12-09 and 2020-01-03. The NCSBE voter registration files show that there was a remarkably high number of registrations dated 2020-01-03. This is due to legislation to accomodate North Carolina's preregistration for young people who are 16 or 17 years old. According to the NCSBE, “To register to vote in North Carolina, eligible voters must be at least 18 years old, but 16- and 17-year-olds may preregister to vote. This means that once you become eligible by age to vote, your voter registration application will then be processed. Until you are registered, you will not be eligible to vote.”. The 2019 ncvoter data shows that there were high numbers of registrations for 17 year olds for 2019-12-09. I have not been able to determine the reason for this, but I will assume it is an administrative action associated with early registration and include those young people along with those registered on 2020-01-03 in my analysis. Any of these 17 year old registrants who were 18 years old at the time of the 2020 general election would qualify to become active voters.
I do not have any way to distinguish between the young people who registered on those two days (2019-12-09 and 2020-01-03) as part of the pre-registration program, and those who did so just coincidentally. However, characterizing each county according to its simple Tukey five number summary applied to the young registrants during 2019 (not including 2019-12-09 and including only weekdays) results in no county where the number of pre-registrants was less than the 2019 Tukey upper-hinge for that county, thus all counties showed a distinct increase in the number of young registrants on the pre-registation days.
This next plot shows pre-registration (on 2019-12-09 and 2020-01-03) in the one hundred North Carolina counties in a comparative setting. The numbers displayed are the percentages of the total pre-registered, and the running total of that percentage. The plot should be read from the bottom upward, the counties at the bottom of the plot having the most pre-registrations. There are a few observations of note, one being the 80% cut marked on the plot, which is comprised of 29 counties. Another is the split near the bottom at about 40% of the running total, constituting a cluster of 5 counties, which is evident from the plot. These counties, in order of their percentage of pre-registrants, are WAKE, MECKLENBURG, GUILFORD, UNION, FORSYTH.