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Growth Model Considerations in Early Literacy Research. Yaacov Petscher Florida Center for Reading Research. What do we want to model?. How students are changing over time Individual differences in change How change in one skill relates to change in another Causes of individual change
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Growth Model Considerations in Early Literacy Research Yaacov Petscher Florida Center for Reading Research
What do we want to model? • How students are changing over time • Individual differences in change • How change in one skill relates to change in another • Causes of individual change • Causes of individual differences in individual change
Progress Monitoring • What does growth in syntax ability look like in K? • Do students differ in their growth patterns in syntax? • What is the relationship between growth in syntax and growth in listening comprehension? • What causes growth in syntax? • What causes individual differences in syntax growth?
So what? • Each model exists for a specific purpose • Differences contribute to individual practical problems • Minimum N • # of Occasions • # of Variables • Can we combine the growth and causal models to extract similar types of information?
Research Questions • What are the growth trajectories of students’ early literacy skills? • Can these be better informed by dynamic developmental relations? • Are there differences in dynamic developmental relations between-students vs. between-classes?
Data and Measures • Sample size = 77,675 students; 4,774 classes • DIBELS Assessments • ISF: Kindergarten • LNF: K-1 • PSF: K-1 • NWF: K-2 • ORF: 1-3 • Something reliability/validity
Analyses • Univariate LCS • Evaluate patterns • Multivariate LCS • Evaluate contributors to LCS • Multilevel LCS • Evaluate differences in estimated effects by classes and students
LNF CFI = .95 TLI = .95 RMSEA = .11 SRMR = .08
PSF CFI = .94 TLI = .95 RMSEA = .09 SRMR = .09
NWF CFI = .90 TLI = .90 RMSEA = .12 SRMR = .09
ORF CFI = .94 TLI = .94 RMSEA = .12 SRMR = .06
LNF .50 – (.16*LNF[t-1]) + (.10*PSF[t-1]) + (.36*NWF[t-1])
How to use the scores • Create vector plots • Determinant importance • Comparing graphs • Relative importance • Screening applications
Multilevel LCS • Model Comparisons • Parallel Process • Constant Change • Fixed Proportional at Levels • Dual Change-Constrained Lag Δχ² (2) = 169, p < .001
Conclusions • LCS can help inform change and causation • May be useful for informing multivariate screening • Better target interventions • They are a pain to run