How do ONS baby name rankings change when variant spellings (e.g., Muhammad/Mohammed) are merged or separated?

1. How the ONS counts names, and the explicit rule behind it

The ONS compiles rankings from birth registration data and treats each exact spelling as a separate entry; it has stated publicly that it does not add together names with similar spellings or shared derivation because doing so introduces subjectivity into the statistics ^{[5] [1]}. News coverage repeats that approach and notes the direct consequence: visually similar or etymologically linked names — for example, Sophia and Sofia — appear as separate ranks on the official list ^{[2] [6]}.

2. What merging variant spellings does to rankings in practice

Combining spellings converts multiple mid- or lower-ranked entries into a single larger total, frequently pushing that aggregated name much higher in the list and sometimes to the top overall; independent analyses that group spellings have found cases where aggregated names leap from outside the top 100 into the top ranks ^{[3] [4]}. The effect is mechanical and predictable: names with many common variant spellings benefit most, while names that are almost always recorded with one spelling are unchanged ^{[7] [4]}.

3. Case study — Muhammad and its variants

ONS 2024 data show Muhammad and multiple other spellings each appearing separately in the top 100 — for instance Muhammad , Mohammed and Mohammad — and the ONS explicitly records each spelling’s count rather than summing them ^{[8] [9] [2]}. Analysts and commentators point out that counting those spellings together would produce a much larger combined total and is the reason repeated claims that “Muhammad is the most popular boys’ name when variants are combined” circulate; ONS has also noted that including variants explains much of Muhammad’s rise in relative prominence over time ^{[1] [10]}.

4. Methods and pitfalls of merging — choices matter

Any attempt to combine names requires rules: which spellings count as the same name, whether anglicised or historic derivatives are included, and how to treat diminutives and nicknames — choices that can dramatically alter results and embed researcher bias ^{[1] [11]}. Different projects use different heuristics — e.g., phonetic equivalence, root etymology, or common usage — and that variation explains why Nameberry’s Playground Analysis produces different “real top names” than official lists, and why critics warn about subjectivity ^{[3] [4]}.

5. Why ONS refuses to aggregate, and the implications for interpretation

ONS rejects aggregation because it would “soon take us into the realms of subjectivity,” a position intended to protect comparability and methodological transparency even though it can understate the cultural prevalence of a name cluster ^{[1] [10]}. The practical implication is that readers and journalists must decide whether they want the strict, replicable snapshot the ONS offers or an interpretive “playground” view that groups variants to reflect how names sound or function socially ^{[5] [3]}.

6. Bottom line for analysts and consumers of the data

The technical answer to how rankings change is straightforward: merging variant spellings increases the combined count and can move a name substantially up the rankings; splitting them (the ONS default) keeps each orthographic variant as a separate entry and can suppress the apparent dominance of any single name form ^{[3] [2]}. Which approach is “right” depends on purpose — legal/administrative clarity favours ONS’s spelling-by-spelling counts, while sociolinguistic or parenting-oriented analyses often prefer aggregated results — and both outputs should be used with awareness of their different assumptions ^{[1] [4] [10]}.