Unique Contributions or - PowerPoint Presentation

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Unique Contributions or Measurement Error? Applying a Bi-factor Structural Equation Model to Investigate the Roles of Morphological Awareness and Vocabulary Knowledge in Reading Comprehension

Michael J. Kieffer

Yaacov

Petscher

New York University Florida Center for Reading Research

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What I’m Not Talking AboutKieffer, M. J. & Box, C. D. (2013). Derivational morphological

awareness,

academic vocabulary

, and

reading comprehension

in

Spanish

-speaking language minority

learners

and their classmates.

Learning

and Individual

Differences, 24

, 168-

175.

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What I’m Not Talking AboutKieffer

& Box

(

2013

):

Inspired by Nagy,

Berninger

, & Abbott (2006)

Derivational MA made a direct unique contributed to reading comprehension, controlling for word reading fluency and academic vocabulary.

Derivation MA made indirect contributions to reading comprehension via both word reading fluency and academic vocabulary.

Predictive relations were largely similar for native English speakers and Spanish-speaking language minority learners

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Morphological Awareness (MA)Students’ metalinguistic understanding of how complex words are formed from smaller units of meaning Starts as a oral language skill, but is developed through interaction with oral and written language

Develops throughout the grades, with derivational MA becoming particular important in upper elementary & middle grades

(

e.g., Carlisle, 1995

; for a review, see

Kuo

&

Anderson

, 2003)

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What we already know

Or at least think we know…

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Morphological Awareness (MA) predicts Reading Comprehension (RC)For a while, we have known that MA is correlated with reading comprehension (e.g., Carlisle, 2000;

Freyd

& Baron, 1982; Tyler & Nagy, 1990)

MA

RC

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MA predicts RC,above & beyond Vocabulary (V)Unique contributions of MA to RC, controlling for vocabulary (e.g., Carlisle, 2000;

Kieffer,

Biancarosa

, &

Mancilla

-Martinez, in press; Kieffer &

Lesaux

, 2008, 2012; Kieffer & Box, 2013; Nagy,

Berninger

, & Abbott,

2006)

MA

RC

V

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But wait…Conceptually, MA and vocabulary knowledge both involve meaning units (e.g., Kuo & Anderson, 2006).

Operationally, measuring MA requires meaningful manipulation of meaning units (e.g., Carlisle, 2012)

MA

V

Are we actually measuring MA and vocabulary as different constructs?

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But wait…Empirically, MA correlates moderately to strongly with vocabulary

(Deacon

, Wade-Woolley, & Kirby, 2007; Deacon, 2011; M J Kieffer &

Lesaux

, 2008;

Mahony

,

Singson

, & Mann, 2000;

Pasquarella

, Chen, Lam,

Luo

, & Ramirez, 2012; Ramirez, Chen, Geva, & Kiefer, 2010; Singson, Mahoney, & Mann, 2000; Wang, Ko, & Choi, 2009; Wang, Yang, & Cheng, 2009

Some observed correlations above .60

(Carlisle, 2000; Ku & Anderson, 2003; Wang, Cheng, & Chen, 2006

)

Are we actually measuring MA and vocabulary as different constructs?

MA

V

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But wait…Observed correlations between MA and vocabulary are attenuated by measurement errorReliability of researcher-created MA measures has been moderate

I

n the .70-.80 range & occasionally lower

So, “unique” contributions of MA beyond V could be an artifact of measurement error

Are we actually measuring MA and vocabulary as different constructs?

MA

V

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Reason to worry…Using Confirmatory Factor Analysis (CFA), Muse (2005) found that MA could not be distinguished from vocabulary in fourth grade (See also Wagner, Muse, &

Tannenbaum

, 2007).

Spencer (2012) replicated this finding with eighth graders.

MA/V

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On the other hand…Using CFA, Kieffer & Lesaux

(2012) found that MA was measurably separable from two other dimensions of vocabulary in Grade 6

though they are strongly related

Neugebauer

, Kieffer, & Howard (under review) replicated this finding for Spanish- speaking language minority learners in Grades 6-8

MA

V

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Research Question 1To what extent do morphological awareness and vocabulary knowledge constitute measurably separable dimensions of lexical

knowledge in

sixth

grade?

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Sample148 sixth graders in 2 suburban schools in Arizona

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SampleSchools reported 81% and 65% of students receiving free or reduced lunch9% designated as English language learners

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MeasuresDerivational Morphological AwarenessNonword suffix choice task (e.g., Nagy et al., 2006)

The man is a great ________.

A)

tranter

B)

tranting

C)

trantious

D)

trantiful

18 items;

Cronbach’s

Alpha = .78VocabularyMultiple-choice synonym task based on Lesaux & Kieffer (2010)

Words drawn from the academic word list (

Coxhead

, 2000)

18 Items;

Cronbach’s Alpha = .74

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MeasuresReading ComprehensionGates-MacGinitie

Reading Test, 4

th

Ed.

(

MacGinitie

,

MacGinitie

, Maria, & Dreyer, 2000

)

Control: Word Reading Fluency

Test of Silent Word Reading

(Mather, Hammill, Allen, & Roberts, 2004 dim|how|fig|blue

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Research Question 1: Data AnalysesUsing item-level data for MA & VocabularyTo investigate dimensionality:

Parametric exploratory factor analysis

Nonparametric exploratory factor analysis

Parametric CFA

Nonparametric CFA

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Modeling Dimensionality of Lexical Knowledge:Unidimensional

Lexical Knowledge

MA2

V1

V2

V3

V18

…

…

MA1

MA3

MA18

Fit poorly

Rejected across parametric & nonparametric EFA & CFA models

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Modeling Dimensionality of Lexical Knowledge:Two Dimensional

MA

MA2

V1

V2

V3

V18

…

…

MA1

MA3

MA18

Vocab

Fit better

Latent factors were strongly related

.78

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Modeling Dimensionality of Lexical Knowledge:Bi-factor Model

MA-specific

Lexical Knowledge

MA2

V1

V2

V3

V18

…

…

MA1

MA3

MA18

Vocab- specific

Fit the best

CFI = .98; TLI = .98; RMSEA = .015

>1D: Δχ² = 66.71,

Δ

df

= 34,

p

<.001

>2D: Δχ² = 48.94,

Δ

df

= 33,

p

<.05

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Findings: DimensionalityMorphological Awareness and vocabulary are measurably separable constructsAt least with these measures and in this population A bi-factor model that accounts for both the overlapping construct of lexical knowledge and the uniqueness of vocabulary and morphological awareness fits best

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Research Question 2To what extent does morphological awareness-specific variance uniquely predict reading comprehension, beyond vocabulary-specific variance and the common variance shared by morphological awareness and vocabulary

knowledge

in sixth grade?

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Research Question 2: Data AnalysesStructural Equation Modeling using a bi-factor model to predict reading comprehension performance

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Predicting Reading Comprehension

MA-specific

Lexical Knowledge

Reading Comp

Word Reading Fluency

Vocab- specific

.67***

.10

.21

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Findings: Predicting Reading ComprehensionIndividually, each of MA-specific variance, vocabulary-specific variance and lexical knowledge strongly predicted reading comprehension.Together, only lexical knowledge had a unique significant association with reading comprehension.

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DiscussionGood news: Results support the common assumption that our measures are capturing different constructs.But we need to keep collecting validity data anyway.

Bad news: What’s unique about MA did not uniquely predict reading comprehension beyond what it shares with vocabulary.

Maybe the unique contribution of MA is less robust than we think.

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Limitations & Future ResearchWe accounted for item-level measurement error, but not task-level measurement error.Statistical power was limited to detect small effects.Small number of ELLs prevented analysis of measurement invariance.

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Thank YouFor more information, email:

michael.kieffer@nyu.edu