The Simple View of Reading: R=DxC
Many models have been put forth
to describe the essential elements involved in reading, but none has proven
to be as robust and useful as what Philip Gough described as the "Simple
View" of reading. In this model, there are two general elements that
are equally important to reading comprehension -- they are decoding skills
and language comprehension skills.
Put differently, a person's ability
to read and understand text can be predicted if you know that person's
ability to decode words and that person's ability to understand spoken
language. If a child is rapid and fluent at decoding text (unfamiliar
words or pseudowords for preference), AND that child has no difficulty
understanding spoken language (implicit understanding of more formal language
for preference), then you can safely predict that child will not have difficulty
with independent reading comprehension.
Research has shown repeatedly that,
in broad strokes, when there are deficits in reading comprehension, there
are always deficits in either language comprehension or decoding skills,
or both -- in fact, most typically both. There are some children
(although it is rare) whose reading comprehension suffers because, while
they are very good at understanding spoken language, they are poor at decoding
text -- these children are called true dyslexics. There are
other children (although very rare) whose reading comprehension suffers
because, while they are good at decoding text, they have difficulties understanding
spoken language -- these children are called hyperlexics.
Most commonly, when a child has difficulty with reading comprehension,
they are having difficulty with both decoding and language comprehension
-- these children are described as having garden variety reading difficulties.
It also makes sense to think of
the relationship between these three variables mathematically, where reading
comprehension is the product of decoding and language comprehension, or
as Gough put it, R=DxC where
R = Reading comprehension
D = Decoding skills and
C = Language comprehension
Imagine that each of these variables
can range in value from 0 to 1. Somebody with perfect ability in
one area would get a 1, and somebody who completely lacks ability in that
area gets a 0 (with most people falling somewhere in between). It
makes sense to think of the relationship as multiplicative, then, because
if you a child is lacking in either decoding skills (D) or language comprehension
skills (C), then reading skills (R) comparably suffer.
Consider a child who gets a perfect
score on a language comprehension assessment (a score of 1), but who performs
poorly on a decoding assessment (a score of 0). This model would
predict that child would perform poorly (a score of 0) on a reading comprehension
If D=0 and C=1, then DxC = 0
And in fact, that is what is found
when real children are tested. Children who are poor at decoding
isolated words are also poor at reading and understanding text, regardless
of how good they are at understanding language. Similarly, children
who are poor at understanding language are poor at reading and understanding
text, regardless of how good they are at decoding words. Researchers
like Ron Carver have confirmed these predictions many times over.
And the other side of the coin has
also been confirmed -- children who are good at decoding isolated words
(fast, fluent, and accurate) and who are good at understanding spoken language
are, on the whole, quite good at reading and understanding connected text.
The predictions made by the Simple View of Reading have been confirmed
many times over.
Given that the formula R=DxC accurately
describes reading, the implications become immediately obvious. First,
we as educators must learn what it takes to help children to be both good
decoders and good language comprehenders. And second, we should structure
our assessment around this model.
There is a framework of reading
acquisition based on the Simple View that addresses the first implication
-- this framework outlines the essential cognitive elements that research
has shown to be important in the development of good decoding skills and
good language comprehension skills. The complete PDF version of the
framework document can be download
here for free, or an on-line
interactive version of the framework is available at the Southwest
Educational Development Laboratory website.
Structuring assessment information
around this framework is trivially easy -- there is an on-line reading
assessment database that allows you to search for published assessments
that test specific knowledge domains that are outlined in the framework.
Further, there is an overview
document describing how each of these assessments is typically assessed.
There are several ways to test a child's knowledge of, for example, phoneme
awareness, and this document describes the different assessment approaches
that can be used to get information about a child's growth in each of these
Beginning of the year Simple Informal Student Reading Survey (for grades 2-8)
By September of every school year, teachers should be able to answer this question -- how well do each of your students read?
More specifically, how many students in your class this year are having
difficulties with reading? Do their difficulties stem from problems
with decoding fluency or language comprehension? Or both?
This is the first question that I try to answer when I encounter a
student struggling with reading -- is it a decoding problem or a language
comprehension problem? The Simple View of reading (R=DxC) tells
us that difficulties with reading comprehension (R) stem from problems
with decoding (D) or comprehension (C). Or both. Determining
this is the first step in diagnosis, and it is the first step in planning
intervention and effective instruction.
Language comprehension problems are easy enough to identify -- if a
student has trouble reading a passage of text, just read the passage of
text out loud to the student. If the student can understand the passage
when she listens to you read it aloud, then her language comprehension skills
are not preventing her from understanding the text. She understands
the material -- she just can't read it independently. It must be a
Decoding is a little thornier, but not much. Most students with
decoding problems are able to correctly identify words and "attack" unfamiliar
words -- they just do it very, very slowly. Those students have problems
with decoding fluency. That's good news because fluency instruction
is quite easy. Some students, however, are not able to accurately
identify words -- especially unfamiliar words they have not seen before.
Those students have more basic word identification issues. These issues
may stem from a lack of phoneme awareness or problems understanding the
To help teachers (2nd to 8th grade) to determine the reading instruction
needs of each of their students, I've created a Simple Formative Reading
Survey (available in PDF). Following this quick survey will help teachers
to figure out what reading-related areas need more instructional support.
2006 -- Current Developments in The Simple View of Reading
Recently, there have been challenges to the Simple View of
reading. At the December, 2005 National Reading Conference in
Florida, esteemed reading researchers Nell Duke and Michael Pressley
hosted (along with a varied panel of experts comprised entirely of
their graduate students) a discussion of the Simple View. It was
the contention of Duke and Pressley and their entire panel of students
that the Simple View is "too simple" to explain the complexities of
reading and learning to read.
This challenge and debate is good and healthy (albeit one-sided), as I
believe every good theory should be challenged and tested through a
process of scientific empirical study. The Simple View, as Duke and
Pressley stated in their presentation, has been overwhelmingly accepted
by the reading research community. It is one of the most widely
accepted models of the reading process, but that doesn't mean that it
should not be challenged and tested. Testing it can only make it
The Simple View is powerful, I believe, for two reasons -- first it has
substantial predictive validity. Other than one reference
(non-peer-reviewed) Nell Duke cited in her presentation, I am aware of
no evidence that has shown any person to be a good reader while being
poor at either Decoding (D) or Comprehension (C). I know of many
studies that have looked for--but failed to find--examples of "Chinese
Readers" proficient with alphabetic text. And I know of many
studies that have used measures of D and C to predict Reading (R) with
The other reason the Simple View is powerful as a model is that it has
very practical implications -- if a student is having difficulty
reading text independently, one can say with confidence that student's
difficulty either stems from difficulties with decoding, difficulties
with language comprehension, or both. There is substantial
research evidence indicating this to be the case.
My advice to teachers is to be conscientious about assessing and
teaching both D and C because both are important for reading success.
Duke and Pressley, in their presentation, alleged that people use
the Simple View to push a "decoding only" agenda. This is clearly
not evidence contradicting the Simple View, however, because anybody
who uses the Simple View to diminish the importance of teaching
comprehension skills is somebody who does not understand the Simple
View. In the Simple View, both D and C are equally important.
Duke and Pressley argued that fluency is an example of a skill outside
the realm of the Simple View. I disagree. Fluency is
usually defined as rapid and automatic decoding plus expressive
prosody. Rapid and automatic decoding is a measure of D, and
prosody is highly related to comprehension. Students who are not
good decoders are not able to rapidly and accurately identify text --
students who have poor comprehension are unable to read with expression
and appropriate prosody.
I can say that most of the seminal research on the Simple View carried
out by Philip Gough did largely use pseudoword identification tasks
(accuracy) to test the Simple View, but that was only because he lacked
the technology to measure fluency in the field testing children on
location in schools. In the more controlled environment of our
lab at the University of Texas, we commonly measured latency responses
and reading rate in examinations of the Simple View. D is defined
as rapid and accurate identification of words or pseudowords. In
fact, in oral naming latency tasks, Phil used to pride himself on
having the fastest average naming latency of any subject in the
study. Phil is my reason for believing that D never really equals
1 -- even when accuracy is perfect, you can still make incremental
gains in speed or fluency.
Duke and Pressley raised the issue of Rapid Automatic Naming or RAN,
but as yet, there are no studies in that vein that contradict the
Simple View. In Naming Latency tasks, Phil was usually able to
identify rare words in about 400 milliseconds, and pseudowords in about
500 milliseconds. I have always been a slow reader, slow in RAN
tasks -- my NL times were in the 500 millisecond range with real words,
and 600 milliseconds with pseudowords. For most tasks, Phil and I
both have adequate resources and skills to perform equally well, but
when pushed to our limits, I am sure that Phil is a better reader than
I am. I suspect differences, such as can be detected, have roots
in different RAN performance. Those differences in RAN affect our
decoding speed. Our differences in decoding speed give rise to
differences in reading volume. (In addition to informational reading,
Phil reads between 100 and 125 books a year for pleasure.) Our
differences in reading volume (and our differences in age) have lead to
substantial lexical and background knowledge differences. Over
years, milliseconds add up.
(Quick Phil story: In Phil's house is a pedestal. On that
pedestal is a well-used unabridged dictionary. When I was in
graduate school working with Phil, Phil sometimes hosted parties for
graduate students at his house. At these parties my fellow
students and I would flip through the dictionary looking for and
calling out words that Phil might not know. In 8 years that I
worked with Phil, I never once found a word he didn't already
know. His vocabulary was enormous because his reading volume was
enormous. And his decoding latency was rapid because his reading
volume was enormous.)
Duke and Pressley stated in their presentation that the Simple View is
not a developmental view -- I strongly disagree with them on this
point. Some years ago, I developed a cognitive framework of
reading development around the Simple View (http://www.sedl.org/reading/framework).
In that framework, I emphasized the developmental elements that are
important in reading acquisition that seem to be less important for
skilled readers. In developing that framework, I started asking
the question, if D and C are so important, what is involved in
developing both D and C? Or more to the point, if a child is
having difficulty with either D or C, what should that child's teacher
focus on in addressing those difficulties? The exercise of
developing a cognitive framework of reading around the Simple View lead
to interesting insights. For example, phoneme awareness is not
important for language comprehension. This was news to a lot of
teachers I worked with who saw PA as a "language skill." And
semantics and syntax are not very useful for decoding -- hard news for
3-Cueing Systems believers, and very important information for teachers
trying to teach students to use semantic and syntactic cues to "guess"
Duke and Pressley argued that the act of skimming, text-search and
navigation, and hypertext were skills beyond the scope of the Simple
View. I would find this more convincing if they were able to show
evidence that there are students who are accomplished at those tasks
without having also developed proficiency as readers. People who
are good at the so called "new literacies" (surfing the web, skimming
informational text, navigating hyper-text pages, etc.) are already
accomplished readers in a traditional sense. Students who
demonstrate proficient skills rapidly skimming around web pages despite
having poor general reading comprehension skills are worthy of further
study if any such student exists, but I do not believe there is any
evidence that they do. I would be quite surprised to find an
individual who is unable to read and comprehend normal,
grade-appropriate passages of text, but can none-the-less skim and
navigate text with celerity and proficiency.
Duke and Pressley represented the Simple View as a one-way causal model
-- with construction of D and C leading to R. This also reveals a
poor understanding of the Simple View. In fact, the Simple View
has always been represented as a two-way model with R reinforcing D and
C. Granted, for every student, the process needs to start
somewhere, and in the beginning, children usually need instruction
in D and C to help them with R. But very quickly, instruction and
practice with R starts reinforcing D and C. So it follows that teaching
reading comprehension skills will help with language comprehension
skills, and vice versa.
In their presentation, Duke and Pressley kept uttering a sentiment that
is quite telling -- they kept saying words to the effect of, "That just
doesn't seem right." That may well be -- but research discussions
take place in the arena of evidence, and as yet, no compelling evidence
has been provided that is at all contrary to the Simple View. In
its simplicity and elegance is power -- power of prediction, power of
explanation, and above all, power to inform instruction.
The theory of evolution may not sit well with some people's feelings,
and some people may have a hard time with the notion that the earth is
round and that it revolves around the sun (and not vice versa).
And that is precisely why we do research -- because feelings can be so
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Last Updated 12-11-2006