In 2021, I wrote a brief piece, Alliterative Affinities: Do Parents Select First Names to Match Surnames? In short, the answer was yes—unless your name starts with a “J”. Unfortunately, the data for the article came from the 1930 Census. Now, I’ve updated the results with much more recent data.

I use up-to-date voter registration data from the North Carolina State Board of Elections. In this update, I’ll ditch the digression on baby names and whether names can have a causal effect on a child’s outcomes in later life.

Let’s say $f$ is an individual’s first initial and $l$ is their last initial. I denote the probability that an individual’s first name starts with “A” as $\mathbb{P}\{f=A\}$, while the associated last-initial value is $\mathbb{P}\{l=A\}$. We’ll consider the probability of an alliterative pair of names beginning with “A”, $$\mathbb{P}\{f=A\wedge l=A\}.$$ I then compare this value to an independent benchmark: $$\mathbb{P}\{f=A\}\times \mathbb{P}\{l=A\},$$ which is the probability of an alliterative pair of names beginning with “A”, if first and last initials were independent. I then calculate the percent difference between these two values $${\mathrm{\Delta }}^A\equiv \frac{\mathbb{P}\{f=A\wedge l=A\}}{\mathbb{P}\{f=A\}\times \{l=A\}}-1.$$

I repeat this process for all letters in the alphabet, $\omega \in \mathrm{\Omega }$. I summarize ${\mathrm{\Delta }}^{\omega }$ in Panel A of Figure 1 for the 18 most common alliterative combinations (as measured by the independent benchmark given above). For the remaining eight letters, the lower denominators result in some exceedingly large ${\mathrm{\Delta }}^{\omega }$ values, all of which are positive. Indeed, ${\mathrm{\Delta }}^{\omega }$ is positive for every letter except “J”; alliterative pairs of “J” are 3% less common than predicted by the independent benchmark. I found this result rather surprising, as I initially expected a positive and relatively large value for ${\mathrm{\Delta }}^J$. As far as I can gather, others are surprised too. Why are alliterative pairs of “J” so salient?

For the top 4 letters—“M”, “S”, “C”, and “B”—alliterative pairs are over 5% more common than would be expected under independence.

I now summarize these results across the alphabet. The probability that an individual has an alliterative name is $$\sum _{\omega \in \mathrm{\Omega }}\mathbb{P}\{f=\omega \wedge l=\omega \},$$ and the probability under independence is $$\sum _{\omega \in \mathrm{\Omega }}\mathbb{P}\{f=\omega \}\times \mathbb{P}\{l=\omega \}.$$

While the independent benchmark predicts an alliterative frequency of 5.35%, 5.74% of names are alliterative. Accordingly, alliteration is 7.3% more likely than would be expected if first and last initial were independent.

In the original article, I excluded married women due to the common practice of adopting a spouse’s last name. I do not observe marital status in this updated analysis. However, given the increase in age at first marriage and (I suspect) decreased tendency of taking a spouse’s last name, I expect gender to matter less compared to the 1930 data. When I restrict the sample to men, alliteration is 7.4% more likely than predicted under independence, a slight increase.