Word ladders: what reading research says about changing one letter

Where word ladders come from

Lewis Carroll, author of “Alice’s Adventures in Wonderland”, published the puzzle as “Doublets” in Vanity Fair on 29 March 1879, and as a small book the same year. His rules: link two words of the same length through intermediate words, each differing from the next in one letter only, with every letter keeping its position. His example runs from HEAD through heal, teal, tell and tall to TAIL.

Carroll says he devised the game at Christmas 1877 for two young ladies, but he also mentions having heard of a similar American game. It is therefore more accurate to say that Carroll popularised the word ladder than that he invented it.

Sources: Carroll, L. (1879) · Doublets: A Word-Puzzle · Macmillan (scan, Internet Archive)

Why changing one letter matters for beginning readers

Learning to read and spell means noticing and changing the individual sounds in a word. Researchers call this phonemic awareness. In 2000, the US National Reading Panel systematically reviewed the research on it.

The panel’s meta-analysis by Ehri and colleagues covered 52 studies. Phonemic awareness instruction clearly improved the skill itself and also helped reading and spelling. It worked best when children manipulated sounds with letters, when it focused on one or two kinds of manipulation, and when it was taught in small groups. Programmes under 20 hours did better than longer ones.

The authors note two limits themselves: spelling did not improve in children with reading disabilities, and phonemic awareness is a means rather than an end – it does not replace a complete reading programme.

Sources: National Reading Panel (2000) · Teaching Children to Read · NICHD reportEhri et al. (2001) · Phonemic awareness instruction helps children learn to read · Reading Research Quarterly

Word building in the classroom: the closest relative of the word ladder

A 2016 practice guide from the US Department of Education’s What Works Clearinghouse explicitly recommends word building: children make a word with letter tiles and then change one letter to make a new word – fat, fan, can, cat. The recommendation is rated as having strong evidence. That rating covers the whole recommendation on phonemic awareness and letter–sound links, though, not word building on its own.

Closest to the word ladder is a small study by McCandliss and colleagues (2003). Children aged 7 to 10 with weak decoding skills worked through chains of words that differed by a single letter in 20 one-to-one sessions. They improved more in decoding, reading comprehension and phonemic awareness than a waiting-list group.

The limits are clear: only 12 children per group remained at the end, the comparison group received no other activity, and the authors call the study preliminary.

Sources: Foorman et al. (2016) · Foundational Skills to Support Reading for Understanding · What Works ClearinghouseMcCandliss et al. (2003) · Design and preliminary tests of the Word Building intervention · Scientific Studies of Reading

Why it might help: every letter–sound link counts

Reading researcher Linnea Ehri describes how words become stored in memory: learners connect each letter to its sound, bonding the spelling, pronunciation and meaning of a word. She calls this orthographic mapping. A word ladder draws attention to exactly one such link – the letter that changes.

A comprehensive review by Castles, Rastle and Nation (2018) explains why letter–sound knowledge is so central at the start of learning to read. This makes a benefit of word ladders plausible, but it is not proof that the puzzle format itself works.

Sources: Ehri (2014) · Orthographic mapping in the acquisition of sight word reading, spelling memory, and vocabulary learningCastles, Rastle & Nation (2018) · Ending the reading wars · Psychological Science in the Public Interest

What the research does not show

We found no study of the word-ladder puzzle format itself, including the popular word-ladder workbooks. The results above come from guided teaching for beginning readers, not from a puzzle solved alone, so their effect sizes cannot be carried over to our daily word ladder.

There is also no evidence that word ladders expand vocabulary or train memory in adults. For grown-ups, a word ladder is first of all a puzzle that is allowed to be fun.

How to use word ladders with children

These are practical suggestions drawn from the studies above – not a tested programme.

• Start with three letters, for example CAT, COT, DOT, DOG. Our daily word ladder has an Easy level for this.
• Say each new word aloud and name the sound that changed.
• Build the words with letter tiles instead of only reading them – working with letters was most effective in the research.
• Keep it short and playful: in the National Reading Panel’s analysis, longer programmes were not more effective than shorter ones.
• Finish by talking about what the words mean and using one of them in a sentence.