The Perfetti Experiments

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What is the role of phonic knowledge in the reading process? Perfetti and his colleagues designed a series of experiment to test this question.

In one study, Perfetti studied third and fifth grade children who had been identified as good and poor readers using a standardised reading assessment. The children were asked to read real and nonsense words (like nust) out loud. Their speed and accuracy was recorded.

In both grades, children were more easily able to accurately and quickly read common, frequently occurring words compared to less common words, and found reading nonsense words the most difficult. However, children who had been assessed as having poor reading comprehension skills found it much more difficult to read the less common words and the nonsense words compared to their peers who were assessed as having good reading comprehension skills (i.e., it took much longer for them to decode the word).

In a second experiment, Perfetti asked fourth graders to read two sentences that ended with a target word. The target word was highly predictable from the context of the sentence, not predictable but semantically plausible or surprising (i.e., highly unexpected but still meaningful).

Good readers were faster and more accurate overall, as you would expect. The two groups performed equally well when words were highly predictable. However, poor reader performed much worse when words were not predictable (i.e., poor readers had a higher reliance on context compared to good readers).

What conclusions can be drawn from these studies?

  • Poor readers have more difficulty decoding (i.e., applying phonic knowledge).
  • Since poor readers can’t decode words, they have to rely more on guessing words from the context.
  • This is an ineffective strategy because they also have more difficulty reading the context words and are poor guessers.
  • Good readers are better at decoding words and therefore less dependent on context.
  • Instead of guessing words, a good reader rapidly identifies each word based on their phonic knowledge and integrates it with the words they have already read.

These experiments were conducted over 30 years ago and the findings have been confirmed many times, yet they are still at odds with how many children are taught!


Perfetti, C. (2007). Reading ability: Lexical quality to comprehension. Scientific Studies of Reading, 11, 357-383.

Perfetti, C., & Hogaboam, T. (1975). Relationship between single word decoding and reading comprehension skill. Journal of Educational Psychology, 67, 461-469.

Perfetti, C., & Roth, S. (1981). Some of the interactive processes in reading and their role in reading skill. In A. Lesgold & C. Perfetti (Eds.). Interactive processes in reading. Erlbaum: Hillsdale, NJ.