1063533
research-article2021
AEIXXX10.1177/15345084211063533Assessment for Effective InterventionNergård Nilssen and Friborg
Original Research
Assessment for Effective Intervention
1–11
The Dyslexia Marker Test for Children: © Hammill Institute on Disabilities 2021
Development and Validation of a New Article reuse guidelines:
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DOI: 10.1177/15345084211063533
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Trude Nergård-Nilssen, PhD1 and Oddgeir Friborg, PhD1
Abstract
This article describes the development and psychometric properties of a new Dyslexia Marker Test for Children (Dysmate-C).
The test was designed to identify Norwegian students who need special instructional attention. The computerized test
includes measures of letter knowledge, phoneme awareness, rapid automatized naming, working memory, decoding, and
spelling skills. Data were collected data from a sample of more than 1,100 students. Item response theory (IRT) was used
for the psychometric evaluation, and principal component analysis for checking uni-dimensionality. IRT was further used
to select and remove items, which significantly shortened the test battery without sacrificing reliability or discriminating
ability. Cronbach’s alphas ranged between .84 and .95. Validity was established by examining how well the Dysmate-C
identified students already diagnosed with dyslexia. Logistic regression and receiver operating characteristic (ROC) curve
analyses indicated good to excellent accuracy in separating children with dyslexia from typical children (area under curve
[AUC] = .92). The Dysmate-C meets the standards for reliability and validity. The use of regression-based norms, voice-
over instructions, easy scoring procedures, accurate timing, and automatic computation of scores, make the test a useful
tool. It may be used in as part screening procedure, and as part of a diagnostic assessment. Limitations and practical
implications are discussed.
Keywords
dyslexia, assessment, computerized, IRT
Dyslexia represents a difficulty in learning to decode print. that phonological problems are present long before formal
Individuals with dyslexia often have problems because they reading instruction begins (Thompson et al., 2015).
do not master the critical factors underlying decoding and It is widely reported however that phonological prob-
spelling, which, in turn, often hamper reading comprehen- lems are neither necessary nor sufficient to account for dys-
sion. To this date, many Norwegian children with dyslexia lexia. Other known underlying risk factors include problems
are missed due to the lack of norm-referenced assessment with learning letters (Torppa et al., 2016), rapid word
tools. A recent report reveals that 51% of the affected indi- retrieval (Parrila et al., 2020), and with working memory
viduals are not identified or diagnosed until they enter high (Peng & Fuchs, 2014). The research literature shows that
school (Solem, 2021). The purpose of this study was to when they operate together with decoding and spelling
develop a dyslexia marker test for Norwegian students and problems, the risk markers accumulate toward a threshold
to examine its psychometric properties. for a diagnosis (Snowling et al., 2020). In a longitudinal
A considerable body of research shows that problems study, Catts et al. (2017) found that children with a phono-
with orthography (Georgiou et al., 2021) and phonology logical awareness deficit in kindergarten were five times
(Snowling & Melby-Lervåg, 2016) are the major proximal more likely to have dyslexia in second grade than children
causal risk markers for dyslexia. In alphabetic languages, without such a deficit. This risk ratio substantially increased
learning to read starts with learning the mapping between with the addition of deficits in both oral language and rapid
phonemes (the smallest units of speech distinguishing one naming. However, some of the children with heightened
word from another) and graphemes (one letter, or a group of
letters, that represent a speech sound, or phoneme). 1
UiT The Arctic University of Norway, Tromso, Norway
Difficulties with the ability to attend to, discriminate, and
Corresponding Author:
manipulate sounds in words are highly likely to lead to dif- Trude Nergård-Nilssen, Department of Education, UiT the Arctic
ficulties with mapping speech and print, or rather, mapping University of Norway, Universitetsvegen 39, Tromsø 9019, Norway.
phonology and orthography. Family risk studies demonstrate Email: trude.nergard.nilssen@uit.no
, 2 Assessment for Effective Intervention 00(0)
risk were later found to be adequate readers, and Catts et al. An increasing number of studies report high stability
(2017) argue for a multifactorial model of dyslexia which into adulthood and that weaknesses in phoneme awareness,
also includes protective factors that offset the impact of rapid naming, and working memory are strong and residual
phonological and other cognitive-linguistic deficits. These correlates of dyslexia (Nergård-Nilssen & Hulme, 2014). At
ideas and similar findings are encapsulated in the multiple the same time, there is a growing body of literature affirm-
deficit model (MDM) originally proposed by Pennington ing the value of providing early reading intervention to
(2006). The two fundamental tenets of the MDM is that struggling readers. For example, Mathes et al. (2005) and
multiple predictors contribute probabilistically to neurode- Lovett et al. (2017) report that children who received inter-
velopmental disorders (e.g., dyslexia) and that shared risk vention in first and second grade, made gains almost twice
factors contribute to comorbidity. McGrath et al. (2020) that of children receiving the same intervention in third
highlight that the clinical and diagnostic implications of the grade and that the early intervention child continued to out-
MDM are that no single cognitive deficit can be used to rule perform the late intervention group. Miciak and Fletcher
in or out dyslexia at the individual level and that the dimen- (2020) highlight that when risk for dyslexia is identified
sional and probabilistic nature of dyslexia (and other disor- before Grade 3, the percentage of children who do not
ders) preclude clear mappings of cognitive profiles to the respond to explicit core and supplemental reading instruc-
diagnosis. In line with these ideas, assessments should tion are reduced to 2%–5%. It is thus critical to have valid
instead focus on the defining symptoms of dyslexia and tests for identifying this group of children available so that
should therefore include brief assessments of reading and intervention can be provided to prevent or ameliorate read-
their proximal skills (Snowling & Hulme, 2021).
ing disorders.
The components underpinning reading performance and
Assessment in all its forms—including screening, diag-
dyslexia appear universal. For example, Landerl et al.
nostic testing, and monitoring—play a key role in any suc-
(2013) found that phoneme awareness and rapid automa-
cessful intervention. Screening can provide an indication of
tized naming were strong concurrent predictors of develop-
which children are “at risk” and would benefit from further
mental dyslexia across six European languages. A logistic
support. A diagnostic assessment, on the contrary, can pro-
regression analysis revealed however that more participants
vide a clear indication of a child’s strengths and weaknesses
were classified correctly when the orthography was more
and specify which skills should be targeted within an inter-
complex. Similarly, Reis et al. (2020) report in their meta-
vention. It also gives a picture of the severity of the child’s
analysis that orthographic transparency has a significant
difficulties and to what extent support needs to be adapted.
effect on the manifestation of dyslexia, with dyslexia symp-
This study presents a norm-referenced test that is named
toms being less marked and weaker in transparent com-
The Dyslexia Marker Test for Children (acronym:
pared to intermediate and opaque orthographies. Numerous
studies furthermore show that in transparent languages, in Dysmate-C). The construction of the Dysmate-C was devel-
which every grapheme roughly corresponds to one pho- oped within the framework of the MDM. The defining
neme, reading accuracy hits the ceiling soon after formal markers are operationalized and construed as liabilities for
reading instruction begins (Torppa et al., 2016). dyslexia and include—in addition to decoding and spell-
Nevertheless—although growth of reading skills is faster ing—letter knowledge, the ability to manipulate speech
and follow a different trajectory in more regular orthogra- sounds (phoneme awareness), and the ability to name com-
phies than in English—phoneme awareness, letter-sound mon symbols at speed (referred to as rapid automatized
knowledge, and rapid automatized naming measured at the naming, or RAN). These markers are identified in cross-
onset of literacy instruction are similarly important as pre- linguistic studies (Caravolas et al., 2019), in individual
dictors of variations in growth rate across languages studies (Thompson et al., 2015), and in meta-analyses
(Caravolas et al., 2019). The Norwegian orthography, in (Snowling & Melby-Lervåg, 2016). The Dysmate-C test
which context this study took place, has consistent graph- was designed to identify children at risk for dyslexia and
eme-phoneme correspondences (feed-forward consistency) who thus need special instructional attention.
but less consistent phoneme-grapheme correspondences Ideally, the psychometric properties of any novel test are
(feedback consistency). Consequently, spelling accuracy is established by comparing how the results of the new test
a bigger obstacle than reading accuracy to young readers agree with the “true” outcome. In this study, some of our
and individuals with dyslexia, and similarly, reading speed experimental instruments could not be validated against
appears to be a bigger obstacle than reading accuracy established measures of the same constructs. In the absence
(Nergård-Nilssen & Hulme, 2014). The test reported here of a Norwegian “gold standard,” we instead examined how
was designed to address these and other characteristic fea- well the Dysmate-C could identify children that were
tures of the Norwegian phonology and orthography by already diagnosed with dyslexia, and thus how well test
including a time-limited word decoding test and a spelling outcomes would reflect our a priori expectations of poor
test that measures orthographic knowledge. performance in this group.
