How name popularity is measured

Lists of the most popular baby names are published every year and widely reported. Behind each list is an official data source with its own rules. Those rules decide what counts as a name, which names appear at all, and how a ranking should be read.

Where the numbers come from

The best-known lists are compiled from official records rather than surveys. In the United States, the Social Security Administration builds its lists from Social Security card applications for births in the United States after 1879. In England and Wales, the Office for National Statistics uses the first names recorded when live births are registered. New South Wales publishes its lists from birth registration data, and National Records of Scotland publishes Scottish figures from birth registrations.

Every spelling counts separately

The rankings for the United States and for England and Wales treat each spelling as a different name. The Social Security Administration says that different spellings of similar names are not combined, and gives the example of Caitlin, Caitlyn, Kaitlin, Kaitlyn, Kaitlynn, Katelyn and Katelynn, each ranked separately. The Office for National Statistics likewise bases its figures on the exact spelling on the birth certificate, and notes that grouping names with similar pronunciation would change the rankings.

This matters. A name spread across several spellings can appear lower in a ranking than it would if all its forms were counted together.

Very rare names are left out

To protect privacy, the lists omit names given to very few children. The Social Security Administration excludes names that would identify fewer than five occurrences in any geographic area. The Office for National Statistics does not release names with fewer than three occurrences in England and Wales, and National Records of Scotland calculates figures only for names given to three or more babies.

Other rules worth knowing

• The US lists are ranked separately by sex and use only the first-name field of the application.
• Many people born in the United States before 1937 never applied for a Social Security card, so early years are less complete.
• The US data is not edited, so recording errors can remain in it.
• In England and Wales, accents are removed when names are processed, and since the 2018 figures hyphenated names have been treated as a single name.
• In New South Wales, recent figures can change because births may be registered some time after they occur.

Reading a ranking carefully

A ranking describes one country or region, in one year, using one agency’s rules. It does not measure worldwide popularity, and figures from different countries are not directly comparable. A useful popularity claim always names its place, its year or period, its ranking or count, and its source.