Duff Fiona J

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Evaluating the effectiveness of a phonologically

based reading intervention for struggling readerswith varying language profiles

Fiona J. Duff Marianna E. Hayiou-Thomas

Charles Hulme

Published online: 6 January 2011 Springer Science+Business Media B.V. 2011

Abstract This study evaluates Reading Interventiona 10-week supplementary

reading programme emphasising the link between phonological awareness and

readingwhen delivered in a realistic educational setting. Twenty-nine 6-year-olds

with reading difficulties participated in Reading Intervention and their progress and

attainments were compared with those of a representative control group from the

same classes, matched on age and gender. Language profiles were also explored.

Children with reading difficulties showed weaknesses in phonological awarenessand literacy as well as nonphonological oral language skills and nonverbal rea-

soning. During the intervention, the intervention group made significantly greater

progress than the control group in early word reading, phoneme awareness and

phonetic spelling. Over a 6-month follow-up period, the intervention group main-

tained its gains but during this time made significantly less progress on single word

reading, phoneme awareness and phonetic spelling than the control group. These

findings provide evidence that reading interventions can be delivered effectively in

standard educational settings. We argue that a better understanding of how to

manage withdrawal of intervention and how to address poor readers additional orallanguage weaknesses is needed.

Keywords Reading disability Intervention Phonology Oral language

Introduction

Extensive research has investigated the most effective methods for ameliorating

word-level reading difficulties. A general consensus is that approaches whichinvolve training phonological awareness and lettersound relationships, while

F. J. Duff (&) M. E. Hayiou-Thomas C. Hulme

Psychology Department, University of York, York YO10 5DD, UK

e-mail: [email protected]

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Read Writ (2012) 25:621640

DOI 10.1007/s11145-010-9291-6


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explicitly linking these skills to the task of reading, are effective for the majority of

children with reading difficulties (for reviews, see Bus & van IJzendoorn, 1999;

NICHD,2000; Torgerson, Brooks, & Hall, 2006; Torgesen, 2005).

Reading Intervention, as developed by Hatcher, Hulme, and Ellis (1994), is an

example of an evidence-based intervention that honours best practice. Its efficacyhas been demonstrated in a number of different studies, across various populations.

In the original study (Hatcher et al., 1994), Reading Intervention (incorporating

phonological awareness linked to reading) was delivered to children aged 7.5 years

who were experiencing reading difficulties. Children received 40 30-min sessions of

individual instruction over 20 weeks. While the Reading Intervention group made

greater progress than the control group on all measures of reading and spelling, the

progress of the other two treatment groups (reading alone and phonology alone) was

akin to that of the control group on all but one measure. The superiority in reading

for the Reading Intervention group was maintained at a 9-month follow-up.Hatcher et al. (1994) provided good evidence for the Reading Intervention

approach, making clear that explicit linkage between phonological awareness and

reading is important, and that training either skill in isolation is not particularly

effective. Findings from two subsequent meta-analyses (Bus & van IJzendoorn,

1999; NICHD, 2000) support this view given that the mean effect size of

phonological awareness training on reading is significantly increased when it is

combined with training in letter knowledge (ds = 0.18 or 0.38, respectively, for

phonological awareness in isolation; ds = 0.66 or 0.67, respectively, with letter

knowledge included).Further rigorous evidence for the effectiveness of Reading Intervention comes

from a randomised control trial (RCT) conducted by Hatcher et al. (2006b). In this

study, Reading Intervention was delivered to children aged 56 years, who

represented the bottom 8% of the population in terms of reading development.

Children were randomly assigned to either a 20-week intervention group or a

10-week (waiting list) intervention group. Reading Intervention was found to

produce improvements in reading, letter knowledge and phoneme awareness

(ds = 0.69, 0.94 and 0.46, respectively). An 11-month follow up showed that gains

in reading had been maintained.

Carefully controlled studies, like those above, are critical for demonstrating that

gains in reading can be attributed to a particular intervention programme. Such

tested programmes can then be passed confidently from researchers to practitioners.

However, it is important to check that the programme continues to produce

educationally significant results, to validate its feasibility and ongoing use. Here, we

report a novel approach to evaluating intervention, which takes the Reading

Intervention programme and assesses its effectiveness when it is initiated and

implemented not by researchers, but by schools as a routine part of their educational

practice.

The timing of this evaluation is also important, owing to significant shifts in

educational policy related to the teaching of literacy in the UK. The Independent

Review of the Teaching of Early Reading (Rose, 2006) recommends that for all

young children, The knowledge, skills, and understanding that constitute high

quality phonic work should be taught as the prime approach to learning to decode

622 F. J. Duff et al.

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(to read) and encode (write/spell) print (p. 70). Therefore, the key principles of

teaching reading that underlie Reading Intervention (e.g. promoting phonological

awareness and phonic decoding) are more familiar elements of whole-class literacy

instruction than they were when Reading Intervention was first developed (Hatcher

et al., 1994), or last evaluated (Hatcher et al., 2006b). Thus, the major aim of thepresent study was to evaluate Reading Intervention, when co-ordinated by schools,

by assessing its efficacy against the evidence-based instructional background of

contemporary literacy education.

Evaluations of interventions usually consider children with diagnosed specific

reading problems. Here, we are interested instead in children that schools deem to

be in need of reading intervention. Preliminary research suggests that such children

might have weaknesses not only in phonological skills but also nonphonological

oral language skills including vocabulary and grammar (Duff et al., 2008). Thus, a

second aim of our work is to explore the linguistic profiles of children identified byschools as needing reading intervention.

To achieve our aims, children with weaknesses in reading participated in Reading

Intervention, and their literacy progress was compared to that of a representative

untreated control group drawn from the same classrooms. This comparison makes

for a conservative evaluation of Reading Intervention: The progress of children with

weaknesses in reading is being compared to that of children whose reading levels

are age-appropriate; and, in the wake of policy shifts, the baseline instructional

environment is one that includes many of the same key elements of the intervention.

Method

A 10-week reading intervention programme was implemented for a group of children

with weaknesses in word reading. Their progress during the intervention period was

compared to that of a representative group of untreated classmates. Children were

tested individually at school on several occasions, following informed parental

consent. A comprehensive test battery assessing literacy, language and cognitive

skills was administered to all children before the intervention began (t1, mean

age = 6;02). Immediately after the intervention finished, relevant literacy-based

skills were re-assessed (t2, mean age = 6;06). The post-test battery was repeated at a

6-month follow-up (t3,mean age =7;00).

Participants

Participants were drawn from eight primary schools in the UK county of North

Yorkshire that were running Reading Intervention in the second and third years of

formal schooling. Children in the intervention group were selected by professionals

within schools, and were identified as children with poor word reading skills who

would likely benefit from Reading Intervention. A representative peer-comparison

group served as the control group. This included children from the same classes

matched individually on gender and age to the intervention children. One

Reading intervention 623

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intervention child was withdrawn part-way through the intervention programme due

to poor attendance. This resulted in a total of 30 participants in the control group

and 29 in the intervention group. Due to changing schools, only 26 children in the

intervention group were assessed at follow up. Further demographic information is

shown in Table1.

Assessment battery

Literacy

Letter-sound knowledge (t1, t2, t3)

Children were shown all 26 letters of the alphabet in a random but fixed order. They

were required to produce the associated sound of each letter.

Spelling (t1, t2, t3)

Children were asked to name pictures of 10 items and to write down each associated

word. A raw score was computed. Spellings were also scored according to how

closely the orthographic representations of the consonants matched the target

consonants: 4 points were awarded for each correct letter; 3 points for a letter that

differed from the target consonant by only one phonetic feature (place, manner or

voicing); 2 points for a partially represented digraph, or for a correct letter in the

wrong position; and 1 point for a letter more than one phonetic feature away from

the target consonant. Vowels were not scored to avoid any confounds owing to

regional variations in accents.

Single word reading (t1, t2, t3)

The BAS II Word Reading subtest (Elliot, Smith, & McCulloch, 1997) was

administered as a standardised test of single word reading. Children were also

administered a 43-item version of the Early Word Reading test (EWRSnowlinget al., 2009), which assessed childrens ability to read words that are frequently

encountered during the early stages of learning to read. A 50-item version of this

test was devised to avoid potential ceiling effects by adding seven more difficult

items from the BAS II Word Reading subtest.

Table 1 Demographics of the control and intervention groups, assessed pre-intervention

Group N Gender Mean age (SD) Range Diagnoses

(M:F) (years;months) (years;months) Dyslexia ADHD SLD

Control 30 15:15 6;02 (0;06) 5;037;03 0 0 3

Intervention 29 14:15 6;02 (0;07) 5;037;02 0 0 7

SLD speech/language difficulties, based on teacher report


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Phonological awareness

Phoneme awareness (t1, t2, t3)

Three subscales from theSound Linkage Test of Phonological Awareness (Hatcher,2000) provided a measure of ability to manipulate phonemes. Children were first

required to blend phonemes, for example upon hearing /t////p/, they were to

produce tap. Next, they were asked to segment phonemes, for example, break up

pet into its constituent phonemes /p/ /e/ /t/. Finally, the children were required to

delete phonemes from the beginning, middle, or end of a word, for example, /g/

from gone makes on.

Nonword repetition (t1)

The Childrens Test of Nonword Repetition (CNRepGathercole & Baddeley,

1996) was administered. Children were required to repeat 40 nonwords which

ranged in length from two to five syllables (e.g. glistow, versatrationist).

Rapid automatized naming (RAN) (t1)

To assess childrens rapid naming ability, the Naming Speed Test from the

Phonological Assessment Battery (PhABFrederickson, Frith, & Reason, 1997)

was administered. Children were first required to name the five relevant objects toensure that they had access to the requisite semantic labels. They were then

presented with a grid containing these five objects repeated at random to create a

series of 50 pictures. Their task was to name these objects in order as quickly as

possible. The task was repeated for a second grid containing the same items but

presented in a different order. Childrens performance was judged according to the

total time in which it took them to complete both trials.

Oral language

Receptive vocabulary (t1)

Comprehension of single words was measured using the British Picture Vocabulary

Scale II(BPVS IIDunn, Dunn, Whetton, & Burley,1997). For a variety of spoken

words, children were required to indicate which of four pictures most accurately

represented each target word.

Expressive vocabulary (t1)

Production of single words was assessed using a confrontation naming testthe

Assessment of Comprehension and Expression 6-11 (ACEAdams, Cooke,

Crutchley, Hesketh, & Reeves, 2001). Children were required to name a series of

pictures that represented a set of 25 nouns gradually increasing in level of difficulty.


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Expressive grammar (t1)

Two tests were administered to assess expressive grammar. In the Recalling

Sentences subtest of the Clinical Evaluation of Language Fundamentals III(CELF

IIISemel, Wiig, & Secord, 1995), children were asked to repeat back a series ofsentences, which increased in complexity and length. The Past Tense Probe from

theTest of Early Grammatical Impairment (TEGIRice & Wexler,2001) was also

administered. On each trial, a sentence relating to a picture was modelled in the

present continuous tense, and the child was then required to talk about the same

picture in the past tense.

Receptive grammar (t1)

The ability to understand grammar in spoken language was measured by theTest forReception of Grammar 2 (TROG 2Bishop, 2003). Upon hearing a sentence,

children had to point to one of four pictures that represented the grammatical

relations between the elements in the sentence (e.g. The elephant chases the duck).

Various grammatical constructions were tested.

Nonverbal ability (t1)

Nonverbal reasoning was assessed using the Pattern Constructionsubtest from theBAS II. Children were required to manipulate two-coloured squares and two-

coloured cubes to replicate abstract patterns which increased in complexity.

Successful replications were credited with points, with additional marks for faster

completion.

Behaviour (t1)

Each childs class teacher completed the Strength and Difficulties Questionnaire

(SDQGoodman, 1997) as a means of assessing childrens behavioural profiles.

Two outcomes are reported: total social deviance (a sum of scores from 4

subscaleshyperactivity, emotional symptoms, conduct problems and peer prob-

lems), and hyperactivity as an independent subscale. Lower scores reflect more

socially appropriate behaviour.

Inhibition (t1)

An estimate of childrens attention skills was provided by the Inhibitionsubscale ofthe Behaviour Rating Inventory of Executive Functioning (BRIEFGioia, Isquith,

Guy, & Kenworthy, 2000). Class teachers rated the extent to which a list of

behaviours typically indicating lack of inhibition (or presence of perseveration),

were evident in each child. Lower scores reflect better attention/inhibition.


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Teaching procedures

The intervention programme implemented in this study was Reading Intervention

(Hatcher et al.,1994,2004,2006a,b). Ten teaching assistants (TAs) were involved

in delivering the intervention, all of whom had received 4 days of training (from thelocal education authority), had previous experience of delivering the programme,

and whose instructional delivery had recently been observed in a quality assurance

exercise. The intervention is designed to run for 10 weeks, alternating between daily

group (n = 3) and individual sessions, lasting 20 min each. All sessions follow a

standard procedure, within which it is possible to tailor the level and focus of

teaching content to individual childrens needs.

Six of the children in the present evaluation received intervention of the

same content but always administered on an individual basisa pragmatic

decision made by the school. Analyses of variance showed that these childrendid not differ significantly from the remaining children in the intervention group

on pre-intervention word reading (Fs(1,27) =0.230.65, ps = .636.429, gp2s =

0.01). Nor did they differ in gains made on most outcome measures during the

intervention (Fs(1,27) = 0.003.62, ps = .979.068, gp2s = 0.000.12). This indi-

vidually tutored group made significantly less progress than the rest of the inter-

vention group on Early Word Reading (F(1,27) =9.91, p = .004, gp2

= 0.27).

Though this may appear contradictory, the NICHD (2000) report is not conclusive

on whether individual instruction is more effective than small-group instruction. In

terms of phonological awareness training, the effects on reading are significantlygreater when instruction occurs in small groups of 27 children (d =0.83)

compared with on a one-to-one basis (d = 0.45). However, there is no significant

difference concerning phonics instruction (small groups, d = 0.43; individually,

d = 0.57).

Group sessions

The group sessions begin with letter and word identification training (6 min)

letters and sight words are introduced and reinforced through multi-sensory

activities (e.g. writing on whiteboards, using tactile letters). The following 8 min are

occupied by phonological awareness activities. Predominately with reference to

Sound Linkage (Hatcher, 2000), children practise blending, segmenting, deleting

and transposing both syllables and (preferentially) phonemes. The link between

sounds and letters is also demonstrated, for example, through simple word-building

activities. Finally, the group narrate a sentence or short story together (e.g. by

describing a picture or event) and each child writes a section from it, in line with

their writing capabilities (6 min). Here, children are explicitly encouraged to deploy

their sound linkage (grapheme-phoneme correspondence) skills to aid spelling. The

TA scaffolds this activity according to each childs needs (e.g. the TA may spell

difficult words or allow children to practise writing a word on a whiteboard before

incorporating it in the final sentence/story).


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Individual sessions

The first activity in the individual sessions involves the child reading an easy book

(4 min)a book that can be read with above 94% accuracy. The childs ability to

read an instructional level book (9094% accuracy) is then formally assessed(5 min); TAs take a running record (miscue analysis) in which they detail reading

accuracy on a word-by-word basis, and categorise the nature of any errors made.

A further 2 min are allowed for making specific teaching points related to the childs

reading strategies (e.g. introducing new sight words, encouraging phrasing and

fluency). Finally, the child is introduced to a new book at the instructional level and

has a first attempt at reading this book alone, followed by a repeated reading with the

TA employing a scaffolding approach to shared reading (9 min). During all reading

activities, children are encouraged to use phonic decoding skills when they encounter

unknown words. For regular words, this might involve the child providing the soundfor every letter in a word and blending those sounds, all through the word, to read it

(Rose,2006). Other strategies, such as the use of contextual and visual cues, are also

taught.

Treatment fidelity

To monitor the fidelity with which the intervention was delivered, all TAs had one

teaching session observed. TAs were rated on the quality with which they delivered

key teaching components of the intervention (1 =

poor; 2 =

satisfactory; 3 =

good).The overall quality (across activities within individual and group sessions) was

deemed good, with an average rating of 2.71 (0.37) and a range of 13. Sessions were

also timed and on average lasted 19.09 (5.94) min (target = 20 min). As these TAs

were experienced in delivering Reading Intervention,and had recently undergone an

independent observation for quality assurance, this suggests that the intervention was

delivered with integrity.

Classroom instruction

Information was obtained from teachers regarding literacy instruction in the

classroom, in which children from both the control and intervention groups

participated. Questionnaires were returned from 6 out of 8 schools (representing 9

classrooms in total). In these schools, phonics was taught daily for around 15 min.

Throughout the week, children generally participated in guided reading as well as

independent or shared reading. More details are given in Table 2.

Results

Evaluation of intervention

The performance of both groups on various outcome measures at t1, t2 and t3 is

shown in Table 3together with Cohensdas a measure of the size of the difference


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between groups at each time of testing. We wished to assess the extent to which the

intervention group made greater progress between pre-test (t1) and the immediate

(t2) and delayed (t3) post-tests, compared to the representative untreated control

group. A series of one-way analyses of co-variance (ANCOVAs) was carried out for

this purpose. Short-term effects were assessed by testing for group differences on

raw scores of various outcome measures immediately after the intervention finished

(t2), controlling for corresponding t1 scores as the covariates. The results of theseanalyses for the intervention period are summarised by the grey bars in Fig.1,

which plots the relative gain in raw score (at the mean of the covariate) for the

intervention group over the control group. Any score greater than 0 represents

an advantage for the intervention group over the control group; where the

Table 2 Nature and frequency of reading instruction in the different classrooms

Classroom Phonics Guided reading Independent

reading

Shared

reading

Paired

reading

Reading cues

encouraged

1 15 mina day

20 min a day Twice aweek

Phonics, pictures,context, sight

word

recognition

2 20 min

a day

3 sessions in

small groups

every week

1 or 2

sessions

a week

Every day Occasionally

3 1520 min

a day

20 min 3 times

a week

Phonics, pictures,

context, sight

word

recognition

4 10 mina day

1520 minonce a week

10 mintwice

a week

Phonics, pictures,sight word

recognition

5 1015 min

a day

Once a week 1 or 2

sessions

a week

Range of methods

6 15 min

a day

30 min twice

a week

30 min

twice

a week

1520 min

3 times a

week

Phonics, pictures,

context

7 15 min

a day

15 min twice

a week

5 min once

a week

Every day 20 min a

week for

some

children

Phonics, pictures,

context, sight

word

recognition

8 15 min

a day

30 min twice

a week

Every day

9 Regularly 20 min

twice a

week

Guided readingan adult working with a small group of children, grouped by ability, to teach strategies

for reading with meaning; independent readingchild reading to himself, to encourage fluency and a

reading habit; paired readingone child reading with one adult or peer; shared readingan adult reading

with a group of children to model and scaffold fluent and expressive reading (with reference to PrimaryNational Strategy,2003)


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95% confidence interval does not cross the x-axis, this represents a statistically

significant effect.

Figure1 shows that the intervention group made significantly greater progress than

the control group on three main outcome measures: early word reading, phonetic

spelling and phoneme awareness. The intervention and control groups made similar

progress in letter knowledge, word reading and absolute spelling. In terms of

individual variation in response to intervention, only 5 out of 29 children in the

intervention group (17%) failed to increase their reading standard scores (where a gain

in standard score represents progress beyond the expected rate). One child dropped

5 standard score points, 1 child dropped 1 point, and 3 children remained stationary

(i.e. showed an expected rate of progress). While there was a general trend for these5 children to perform at a slightly lower level on most measures at t1, the only

significant difference was on phonetic spelling (F(1,25) = 5.84,p = .023, gp2

= 0.19).

The use of ANCOVA to evaluate the effects of intervention relies on the

assumption of equivalent regression slopes between groups. We assessed this in a

Table 3 Means (standard deviations) and effect sizes on outcome measures at pre-intervention (t1), post-

intervention (t2), and 6-month follow-up (t3) for the control and intervention groups

Measure Test point Max. Control Intervention Effect

size (d)

Letter knowledge t1 26 24.57 (3.19) 24.21 (2.06) 0.13

t2 25.13 (2.36) 25.38 (1.18) 0.13

t3 25.77 (0.82) 25.85 (0.46) 0.16

Early word reading t1 50 25.47 (14.54) 11.03 (8.70) 1.21***

t2 32.37 (14.98) 22.31 (12.12) 0.74**

t3 38.63 (12.29) 29.38 (11.81) 0.77**

Word reading, raw t1 90 20.43 (14.95) 8.10 (7.72) 1.04***

t2 29.67 (17.61) 16.17 (11.36) 0.91**

t3 39.40 (16.89) 22.19 (13.25) 1.13***

Word reading, standard t1 101.73 (15.29) 87.72 (9.73) 1.09***

t2 106.43 (15.77) 94.45 (9.71) 0.91**

t3 109.03 (13.73) 93.62 (10.77) 1.25***

Spelling, raw t1 10 2.90 (1.84) 1.03 (1.27) 1.18***

t2 4.17 (2.48) 2.52 (1.74) 0.77**

t3 5.33 (2.25) 3.31 (2.31) 0.89**

Phonetic spelling t1 92 76.70 (18.99) 60.41 (20.27) 0.83**

t2 81.17 (15.25) 76.86 (9.60) 0.34

t3 86.77 (6.50) 80.19 (10.06) 0.78**Phoneme awareness t1 18 10.50 (4.23) 5.97 (4.78) 1.00***

t2 11.17 (4.09) 9.83 (4.25) 0.32

t3 13.07 (2.85) 10.65 (4.24) 0.67*

N.B. Group differences tested with one-way analyses of variance: * significant at p\ .05; ** significant

at p\ .01; *** significant at p\ .001 At t1 and t2, control group N = 30, intervention group N = 29; at t3, control group N = 30, inter-

vention group N = 26


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series of regression models in which we entered the Covariate, Group (coded 0,1),

and the Group 9Covariate interaction term as predictors of outcome. In all cases,

except for phonetic spelling, the Group 9 Covariate interaction term was nonsig-

nificant (bs =

0.001.20, ts =

0.021.57, ps =

.121.983), which supports the useof an ANCOVA model with fixed slopes across groups. For phonetic spelling the

Group 9 Covariate interaction was significant indicating non-equivalent slopes

between groups [b = -0.34,t = -3.95,p\ .001; the slope relatingt2 scores tot1

scores was steeper in the control group (b = 0.90) than in the intervention group

(b = 0.80)]. In this model, however, there was a highly significant difference in

marginal means scores between the groups at the mean level of the covariate, of

4.58 points in favour of the intervention group (v2 = 6.37, p = .012). This

difference became progressively larger at lower levels of the covariate (initial

phonetic spelling score). The results of this analysis confirm that there is a reliable

effect of the intervention on phonetic spelling for children at the mean of the

covariate and below, but that the effects of the intervention reduce to nonsignificant

levels for children who start out with higher phonetic spelling scores.

Long-term effects of the intervention were evaluated in a similar way, this time

testing for group differences 6-months after the intervention finished (t3), with

corresponding t2 scores as the covariates. The results of these ANCOVAs for the

maintenance period are represented by the white bars on Fig. 1. Any score less than

0 represents a relative advantage for the control group, over the intervention group;

where the 95% confidence interval bars cross the x-axis, this represents a

statistically significant effect.The ANCOVAs show that after the intervention had ceased, the intervention

groups progress on tests of letter knowledge, early word reading and absolute

spelling did not differ from that of the control groups, and that its progress on

phoneme awareness, phonetic spelling and word reading was significantly slower.

-12

-10

-8

-6

-4

-2

0

2

4

6

8

10

lette

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dge

phon

emeaw

aren

ess

early

wordreadin

g

wordreadin

g

spellin

g

phon

etic

spellin

g

lette

rkno

wle

dge

phon

emea

wareness

early

wordreadin

g

wordreadin

g

spellin

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phon

etic

spellin

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Relativeraws

corega

in

0.22

0.71

0.37

0.10

0.13

0.61

-0.13 -0.25

0.03

-0.29 -0.19 -0.17

Fig. 1 Relative advantage in raw scores (with 95% confidence intervals) on outcome variables for

the intervention group over the control group across the intervention period (in grey bars) and the

maintenance period (in white bars). Effect sizes (Cohens d) hover above the bars, calculated as the

difference between groups on raw gain scores divided by the pooled standard deviation of the covariate


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Analyses demonstrated that most variables met the assumption of homogeneity

of regression slopes (bs =0.082.00, ts =0.75 1.46, ps = .151.455)allowing

a fixed slopes, varying intercepts ANCOVA. The assumption was not met for

phonetic spelling [b = 0.44, t = 3.93, p\ .001; the slope relating t3 scores to t2

scores was steeper in the intervention group (b = 0.79) than in the control group(b =0.70)]. In a model including the Group 9 Covariate interaction, however,

there was a significant difference in marginal means scores between the groups at

the mean level of the covariate, of 4.04 points in favour of the control group

(v2 =7.26, p = .007). This difference became progressively larger at lower levels

of the covariate (phonetic spelling score at immediate post-test).These results show

that, for those whose post-test phonetic spelling scores fall at the mean of the

covariate and below, children in the control group are progressing more than those

in the intervention group on phonetic spelling during the maintenance period. This

difference in progress reduces to nonsignificant levels for children who have higherphonetic spelling scores at immediate post-test.

The measure of phoneme awareness also failed to meet the assumption of

homogeneity of regression slopes [b = 0.39, t = 2.13, p = .151; the slope relating

t3 scores to t2 scores was steeper in the intervention group (b = 0.87) than in the

control group (b = 0.85)]. As with phonetic spelling, in a model including the

Group 9 Covariate interaction there was a significant difference in marginal means

between the groups at the mean level of the covariate, of 1.42 points in favour of the

control group (v2 = 8.12,p = .004). This difference became progressively larger at

lower levels of the covariate (phoneme awareness at immediate post-test).Thus, forthose whose post-test phoneme awareness scores fall at the mean of the covariate

and below, children in the control group are progressing more than those in the

intervention group on phoneme awareness during the maintenance period. Again,

this difference in progress reduces to nonsignificant levels for children who have

higher phoneme awareness scores at immediate post-test.

In sum the intervention was shown to be effective. On three key literacy

measures (phoneme awareness, reading and spelling) the progress made during the

intervention period by a group of children selected as having poor reading skills was

greater than the progress made by a representative group of children who received

regular classroom teaching (including daily phonics training and reading practice

for most children). However, the rate of progress of the children in the intervention

group was not sustained once intervention was withdrawn. During this maintenance

period, their progress on letter knowledge, early word reading and spelling was not

different from that of the control groups but their progress on word reading,

phoneme awareness and phonetic spelling was significantly slower (at least, for the

latter two variables, for children performing at lower levels at the end of the

intervention).

Learner profiles

To obtain a better understanding of the characteristics of children selected to take

part in Reading Intervention, their abilities on a range of linguistic, cognitive and

behavioural measures were compared to those of the control group (see Table 3).


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As expected, the control group performed significantly better than the intervention

group on all measures of reading and spelling, with large effect sizes. The difference

in letter knowledge was not significant, though this reflects ceiling effects in both

groups. Performance on the remaining measures is shown in Table4. The

intervention group displayed significant deficits in phonological skills, as measured

by phoneme awareness and rapid object naming, though it did not differ

significantly from the control group on nonword repetition. The intervention group

performed significantly worse than the control group on all measures of grammar,

but both groups showed age-appropriate receptive vocabulary knowledge. Finally,

the two groups were equated in terms of their behavioural and attentional skills, but

the intervention group performed significantly worse than the control group on the

test of nonverbal reasoning.

Children were selected for Reading Intervention according to relative weaknessesin reading, based on teacher evaluations. Restricting profile analyses to children

who reach an objective definition of a reading deficit will give a more accurate

picture of the language profiles of such children. A reading deficit was quantified as

performance on the Early Word Reading test at least 1.25 SD below the control

Table 4 Comparing the means (and standard deviations) of the control (N = 30) and intervention

(N = 29) groups on a variety of cognitive, linguistic, and behavioural measures at t1

Measure Score Max. Control Intervention Effect

size (d)

Nonword repetition Raw 40 25.50 (5.93) 23.14 (7.43) 0.35

Standarda

105.03 (14.80) 98.93 (15.39) 0.41

Rapid naming Seconds 139.70 (32.62) 163.16 (33.04) 0.71**

Standardb 97.35 (14.16) 80.00 (14.97) 1.19**

Receptive vocabulary Raw 168 64.27 (13.28) 60.97 (14.77) 0.23

Standard 102.77 (11.97) 99.55 (12.24) 0.27

Picture naming Raw 25 8.87 (4.09) 6.72 (4.21) 0.52

Standardb

10.40 (2.48) 7.89 (2.89) 0.93**

Receptive grammar Raw 20 8.07 (3.61) 6.24 (3.18) 0.54*Standard 89.40 (15.59) 80.79 (13.48) 0.59*

Recalling sentences Raw 78 23.13 (9.24) 16.45 (9.92) 0.70*

Scaledb

8.55 (2.87) 5.61 (2.15) 1.16**

Past tense production Percentc 100 70.79 (12.10) 60.59 (17.19) 0.69*

Nonverbal reasoning Raw 59 26.60 (9.16) 20.76 (9.66) 0.62*

T-score 52.60 (9.50) 44.93 (10.02) 0.79**

Hyperactivity Raw 10 3.73 (2.88) 4.69 (2.98) 0.33

Total social deviance Raw 40 8.77 (6.55) 9.62 (5.44) 0.14

Inhibition Raw 30 14.47 (5.08) 14.86 (4.43) 0.08T-score 52.87 (9.68) 54.07 (11.54) 0.11

a Control group N = 30, intervention group N = 27; b Control group N = 20, intervention group

N = 18; c Control group N = 28, intervention group N = 27

* Significant at p\ .05; ** significant at p\ .01; *** Significant at p\ .001; p = .051


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group mean; this cut-off was chosen so that around 15% of children in the control

group were characterised with a reading deficitin line with normal distribution. In

all, 15 children met the inclusion criterion (4 control and 11 intervention children).

Deficits in aspects of oral language were defined in a similar way (at least 1.25 SD

below the control mean). Composite z-scores were created for vocabulary (recep-tive and expressive vocabulary) and grammar (receptive grammar and recalling

sentences). Phonology was represented by phoneme awareness skills. The measure

of nonverbal reasoning was used to define difficulties beyond language.

The prevalence of additional deficits in children with or without a reading deficit

is given in Table5. The frequencies suggest that language deficits are more

prevalent in children with reading deficit than those without. Indeed, chi-square tests

revealed that language and reading deficits are non-independent; classification of the

presence of a language deficit is contingent upon presence of a reading deficit. In

contrast, nonverbal deficits were independent of reading deficits; children were

equally likely to have a nonverbal deficit regardless of reading status.

The co-occurrence of reading and language deficits in individual children were

then considered. Forty-six percent of children with a reading deficit had an isolated

phonological deficit (compared with 7% of children without reading deficit).

However, deficits in phonology also patterned highly with deficits in nonphono-

logical oral language: 47% of children with a reading deficit had co-occurring

deficits in phonology and vocabulary or grammarusually both (compared with

9%). In contrast, isolated difficulties in nonphonological oral language skills in the

presence of intact phonological skills did not feature in children with a reading

deficit (compared with 11% of children without a reading deficit).

Summary of results

A 10-week reading intervention programme was delivered by trained TAs to 6-year-

old children who had been identified by their teachers as exhibiting relative

weaknesses in word reading. The progress of these children was assessed before and

after the intervention, and compared with a representative sample of age- and

gender-matched children from the same classrooms. The intervention group made

significantly greater gains over the course of the intervention than a representativecontrol group from the same classrooms on phoneme awareness, early word reading

and phonetic spelling. These gains were maintained over a 6-month no-intervention

maintenance period; though in general children in the intervention group were

progressing at a slower rate than those in the control group.

Table 5 Prevalence of

additional deficits in children

with or without a reading deficit

N.B. Critical values ofv2 with 1

df: 3.84,p = .05; 6.64, p = .01;

10.83, p = .001

No reading deficit

(N = 44)

Reading deficit

(N = 15)

v2 p

Phonology 7 (16%) 14 (93%) 29.84 .001

Vocabulary 6 (14%) 6 (40%) 4.80 .05Grammar 4 (9%) 6 (40%) 7.61 .01

Nonverbal 11 (25%) 5 (33%) 0.39 NS


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Comparisons of the two groups prior to the intervention indicated that children who

were identified by their teachers as needing Reading Intervention showed relative

weaknesses in literacy and phonology, as expected, but also wider difficulties in

nonphonological oral language (vocabulary and grammar) and nonverbal ability. This

pattern was confirmed in a profile analysis, which demonstrated that deficits in bothphonological and nonphonological aspects of oral language frequently co-occurred

with reading deficits.

Discussion

Previous research has demonstrated that the Reading Intervention programme

successfully improves the reading abilities of struggling readers. This study aimed

to build on this evidence base by conducting an educationally realistic evaluation ofReading Intervention, carried out in the wake of recent shifts in educational policy

relating to general reading instruction (e.g. Rose, 2006). The present study also

investigated the linguistic profiles of children selected by their teachers to

participate in Reading Intervention.

Twenty-nine 6-year-old children with reading difficulties who received Reading

Intervention underwent a comprehensive cognitivelinguistic assessment, and

performance on key phonological and literacy tasks was measured before and after

intervention. The progress of the intervention groups was compared with that of a

control group (children from the same classes, matched on age and gender). ReadingIntervention was again associated with improvement in key literacy skills. In

addition to expected deficits in phonology and literacy, some children with reading

difficulties demonstrated significant weaknesses in nonphonological oral language

(vocabulary and grammar).

Efficacy of reading intervention

The present evaluation of Reading Intervention adds to previous studies which

demonstrate its effectiveness in improving literacy skills of struggling readers (after

Hatcher et al., 1994, 2004, 2006a, b). Here, the intervention and control groups

made significant progress throughout the intervention period. After controlling for

differences in baseline performance, the groups made statistically equivalent gains

on a standardised test of word reading, letter knowledge and absolute accuracy of

spelling attempts. Crucially, the intervention group demonstrated significantly

greater progress than the control group in early word reading, phoneme awareness

and phonetic spelling (though for the latter variable, this effect was only significant

for children who started out with lower levels of phonetic spelling). It must be noted

that children in the intervention group remained significantly behind their peers in

single word reading and spelling skills.

A common metric for comparing intervention studies is the number of standard

score points in reading gained per hour of intervention (McGuiness, McGuiness, &

McGuiness,1996). A review of reading interventions which incorporate training in

phonemic awareness and phonemic decoding (akin to Reading Intervention) reports


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an average increase of 0.20 standard score points per hour (Torgesen et al., 2001).

The present implementation of Reading Intervention obtained an average gain of

0.59 standard score points per hour, which compares very favourably with previous

studies. Furthermore, only 5 of 29 children in the intervention group (17%) failed to

show an increase in reading standard score over the intervention period. Thisstatistic also compares well to other studies (e.g. Hatcher et al., 2006b).

The progress of all children was monitored 6 months after the intervention had

finished. In both groups, maintenance or even continued progress in literacy skills

was shown. Strikingly, while the intervention group either equalled or excelled the

control groups rate of progress during the intervention period, their rate of progress

lagged behind that of the control group during the maintenance period. Though

confirming the effectiveness of Reading Intervention, this implies that some poor

readers may need support for longer than 10 weeks. Future research might pursue

the hypothesis that children who are gradually phased out of Reading Interventionafter 10 weeks will demonstrate better maintenance of treatment gains than those

who experience an immediate cessation.

When drawing conclusions from this study, it must be borne in mind that there was

a lack of random assignment of children to groups, and that groups were not matched

on literacy skills at the outset. While we acknowledge that an RCT would have been

preferable, we nonetheless argue that the results are still meaningful. On the basis of

previous RCTs (e.g. Hatcher et al., 2006b), we have good reason to suppose a priori

that Reading Intervention is causal in producing gains in literacy. Furthermore, the

very design of this study is conservative. Children were selected by their teachers toreceive intervention on the basis that they had weaknesses in reading relative to their

peers; that is, they had been showing slower progressachieving a lower level of

literacy compared to their peers, despite the same length of instruction. It is therefore a

reasonable assumption that the intervention groups progress would have continued to

be relatively slower, had the intervention not been effective. Yet our results show that

these poor readers made more progress than a representative group of children who

themselves were making at least average progress in reading. Finally, the relatively

slower pace of progress of the intervention group in the no-intervention follow-up

period confirms this treatment effect.

Learner profiles

A second aim of this study was to assess the linguistic profiles of children with

reading difficulties. Children selected to receive Reading Intervention tended to

display weaknesses in expressive and receptive grammar and expressive vocabu-

lary, in addition to their expected weaknesses in phonological skills.

The children given intervention in this study were selected by their teachers as

having reading difficulties, relative to their class peers. Consequently, the degree of

reading difficulty varied across schools, and not all children included in the

intervention group would have difficulties enough to qualify as reading disabled

according to typical diagnostic criteria. This observation is in line with other

research which shows that while teachers are good at identifying the children at-risk

of dyslexia (good sensitivity), they tend to over-estimate the number of children


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who are truly at-risk (poorer specificity; Snowling, Duff, Petrou, Schiffeldrin, &

Bailey, in revision).

To gain a more accurate understanding of the co-occurrence of reading and

language difficulties, the whole sample was re-categorised according to the presence

or absence of a reading deficit, as defined relative to the average readingperformance of the control group. Language (but not non-verbal) deficits were

significantly more likely to occur in children with a reading deficit, compared to

those without. A large majority of children with reading deficits had a phonological

deficit (93%). Interestingly, the occurrence of this phonological deficit was split

across two sub-types of reading disability: 46% of those with reading deficits had a

concomitant deficit in phonological aspects of oral language alone; another 47% had

co-occurring deficits in both phonological and nonphonological aspects of oral

language. Such profiles approximate both classic dyslexia and its broader

phenotype, respectively (Scarborough, 1990; Snowling, Gallagher, & Frith, 2003;Snowling, Muter, & Carroll,2007). These results mirror the findings of Catts, Fey,

Zhang, and Tomblin (1999), who tracked the development of a large sample of

children, categorising them as either good or poor readers in their third year of

schooling, and retrospectively considered their language skills at school entry. Both

studies support the conclusion that weaknesses in nonphonological oral language

feature among a significant proportion of children identified primarily for their

reading difficulties.

It is important to consider why broader oral language difficulties are observed in

children who present primarily with a reading deficit. The most prominent theory ofdyslexia (and by extrapolation, reading disorders) asserts that the main cause is a

core deficit in phonological processing (Stanovich, 1988; Vellutino, Fletcher,

Snowling, & Scanlon, 2004). At first blush, this explanation would not anticipate

concomitant deficits in broader oral language skills; nonetheless, some attempt may

be made at reconciling these broader language deficits within this theoretical view.

In terms of vocabulary skills, the children selected for Reading Intervention

exhibited average receptive skills, with a tendency for weaknesses in expressive

skills. It is hypothesised that expressive vocabulary is more closely related to word

reading, as task performance necessitates access to fully specified phonological and

semantic representations (Chiappe, Chiappe, & Gottardo, 2004; Wise, Sevcik,

Morris, Lovett, & Wolf, 2007). Children with dyslexia are known to struggle with

word finding and confrontational naming and these problems are commonly assumed

to stem from phonological weaknesses, either in the encoding or accessing of

phonological representations (Nation, Marshall, & Snowling, 2001; Snowling, van

Wagtendonk, & Stafford, 1988; Swan & Goswami, 1997; see Messer & Dockrell,

2006 for discussion). The current study also found poor morphological skills in

children participating in Reading Intervention; it has been argued elsewhere that

morphological impairments may be caused by a phonological deficit (Bird et al.,

2003; Chiat,2001; Joanisse & Seidenberg,1999).

Thus, the observation of expressive vocabulary and morphological deficits in

children with reading difficulties is not necessarily incompatible with the

phonological deficit hypothesis. Notwithstanding this, it is less clear how the

observed deficit in receptive syntax could be accounted for by weaknesses in


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phonological processing. The precise nature and direction of the relationship

between the various subdomains of oral language (phonology, morphosyntax and

semantics) requires further study, and this will have implications for theories of

reading development and disorders. However, the critical point for present purposes

is that these subdomains of oral language are likely to interact. Coupling this withthe knowledge that reading disorders are characterised by a primary deficit in

phonological processing (Vellutino et al., 2004), it becomes unsurprising that

nonphonological oral language difficulties are observed in children with reading

disability.

Clearly, future longitudinal studies need to assess the nature of the relationships

between intra-domain (phonological and nonphonological oral language) and inter-

domain (oral and written language) deficits in children at risk of reading difficulties.

Summary and conclusions

This study adds to earlier evaluations of Reading Intervention and shows that when

delivered in an educationally realistic way, it is associated with improvements in

fundamental literacy skills. The findings support growing evidence that deficits in

both phonological and nonphonological aspects of oral language co-occur with

reading difficulties. Such data are in line with the thesis put forward by Snowling

(2008) that a phonological deficit is the main cause of reading difficulties, but that

this risk factor may be moderated by weaknesses in broader (nonphonological) orallanguage weaknesses. The finding that weaknesses in nonphonological areas of

language typify a significant proportion of children with reading difficulties suggests

that future intervention programmes ought to address both phonological and

nonphonological aspects of oral language as foundations for literacy development.

Acknowledgments The present study was funded by the Biotechnology and Biological Sciences

Research Council. Grateful thanks are extended to Maggie Snowling for her input, to North Yorkshire

Children and Young Peoples Services for support of this work (particularly Simon Gibbs and Glynnis

Smith), and to all of the pupils, teaching assistants and schools who participated.

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