skip to main content skip to footer


ETS News & Insights


Teacher teaching students in a classroom

The Critical Role Decoding Plays in Reading Comprehension

March 9, 2020

Learning to read is a complex process that involves the coordination of a wide range of skills. Some of these skills enable children to recognize words in printed text, while others allow them to extract meaning and build coherence from text. As students progress through elementary school, their proficiency is assessed to gauge foundational reading skills, such as decoding, fluency and vocabulary, which are integral for reading comprehension.

In an ideal world, those identified as having foundational skills deficits receive additional instruction to help them improve and, hopefully, become better readers. But for some, these skills gaps may go undetected. If students are not identified early on, the problems may persist, and proper instruction may not be provided to get them back on track.

According to NAEP (PDF), known as the “Nation’s Report Card,” about two thirds of students from public schools across the nation read below the proficient level in 2019. The National Council on Teacher Quality (NCTQ®) (PDF) argues that those woes could be reduced if more teachers knew how to improve the reading abilities of students. One area that has received recent attention in this regard is foundational reading skills, such as phonics and decoding.

Decoding skills, which help students recognize printed text as words, are prerequisite to reading comprehension. However, many students are what could be classified as “poor decoders.”

In recent work on the core competency of decoding, we published a study in The Scientific Studies of Reading in which we discussed specific behaviors of “poor decoders” and subsequently proposed potential remedies to address this critical issue. Our work focused on students who were above grade 5 because it is commonly believed that in the United States, students should have adequate decoding skills by then, sufficient for them to read on their own.

To break the decoding cycle, we recommend identifying “poor decoders” through proper assessment. If students have comprehension issues, testing their foundational skills can help determine if they are limiting reading comprehension.

Tenaha O'Reilly, Principal Research Scientist at ETS

The decoding process

Decoding is a process which allows one to recognize a word. When reading, the proficient student recognizes grade-level appropriate words automatically without much effort. When an unfamiliar word is encountered, the reader may try to pronounce it by applying alphabetical principles (i.e., knowledge of letter-sound correspondence). If the pronunciation of the unfamiliar word matches with a word in the reader’s spoken vocabulary, the word will be recognized, and reading continues.

But what if this process of pronouncing a word doesn’t help with word recognition? What we observed is a differentiator between normal decoders and “poor decoders.” Some children — the normal decoders — will spend a longer period trying to decode an unfamiliar word. On the contrary, “poor decoders” will not be as persistent and will give up more quickly.

Looking at the big picture, we found that “poor decoders” typically:

  • Are slower in recognizing familiar words by sight;
  • Are slower in recognizing unfamiliar words through decoding;
  • Spend less time trying to decode words that are new to them; and
  • Therefore, the combination of slower decoding and less time spent on decoding means they are getting less practice in decoding over time, which leads to less decoding growth in the long run.

In other words, poor decoders may be trapped in a vicious cycle: poor decoding skills combined with less time spent attempting to decode novel words interferes with decoding development. This in turn leads to poor reading comprehension.

So, what can be done?

Results from our study show that students’ processing times on different types of decoding items can provide useful information for identifying students whose decoding might become stagnant.

The first step in breaking this cycle is to identify “poor decoders” through proper assessment. If students have comprehension issues, we recommend testing their foundational skills to determine if they are limiting reading comprehension. If there are problems with skills such as decoding, students need intervention. For some, who never received phonics instruction, time might need to be spent on learning the basics and students should be given ample practice to build their skills over time.

Overall, poor decoders must be persuaded to be persistent in their decoding practice and should spend a longer time trying to decode new words they encounter. The adage, “practice makes perfect,” comes to mind. When slower processing translates into more opportunities to practice, it will probably lead to faster development in decoding.

The research reported here was supported by the U.S. Department of Education Institute of Education Sciences, Award Number R305F100005, to Educational Testing Service as part of the Reading for Understanding Research Initiative. The opinions expressed are those of the authors and do not represent views of the U.S. Department of Education or Educational Testing Service.

Zuowei Wang is a Research Scientist in the Center for Research on Human Capital and Education at ETS. Tenaha O’Reilly is a Principal Research Scientist in the Center for Research on Human Capital and Education at ETS.