DOI: 10.5061/dryad.sj3tx96g9
title: Maximizing outcomes for preschoolers with developmental language disorders

description: This dataset contains de-identified baseline and short-term follow-up data
 from a randomized controlled trial examining the effects of Enhanced
 Milieu Teaching–Sentence Focused (EMT-SF), an 18-month, multi-phase
 caregiver-implemented intervention for children at risk for developmental
 language disorder (DLD) (ClinicalTrials.gov: NCT03782493). The trial
 enrolled 108 children between 30 and 31 months of age and their
 caregivers. Children were randomly assigned to either the EMT-SF treatment
 group or a control condition. Seven participants who did not consent to
 additional data sharing are excluded from this dataset. The dataset
 includes assessments collected at three time points: baseline (T30; child
 age ~30 months), 6 months post-baseline (T36; child age ~36 months), and
 12 months post-baseline (T42; child age ~42 months). Baseline measures
 include standardized language assessment data from the Preschool Language
 Scales, Fifth Edition (PLS-5), standardized language sample variables,
 child–caregiver interaction (CCX) measures, and demographic
 characteristics. At T36, data include repeated language sample and CCX
 measures as well as receptive and expressive vocabulary assessments from
 the Peabody Picture Vocabulary Test, Fifth Edition (PPVT-5) and the
 Expressive Vocabulary Test, Third Edition (EVT-3). At T42, data include
 repeated language sample and CCX measures and grammar assessments from the
 Structured Photographic Expressive Language Test–Preschool, Second Edition
 (SPELT-P2) and the Test of Early Grammatical Impairment (TEGI). The
 primary analyses examined short-term vocabulary outcomes at T36 and
 grammar outcomes at T42 using structural equation modeling (SEM) with
 latent variables representing vocabulary and grammar constructs. Results
 of analyses conducted on this shared dataset may differ slightly from
 published findings due to the exclusion of participants who did not
 consent to data sharing. This dataset enables replication of published
 analyses and supports secondary analyses examining early vocabulary
 development, grammar development, caregiver-implemented intervention
 effects, and longitudinal language trajectories in children at risk for
 DLD.
description: # Maximizing outcomes for preschoolers with developmental language
 disorders Dataset DOI: [10.5061/dryad.sj3tx96g9](10.5061/dryad.sj3tx96g9)
 ## Description of the data and file structure The data included here were
 gathered from the U01 grant "Maximizing outcomes for preschoolers
 with developmental language disorders" awarded to Dr. Megan Roberts
 at Northwestern University. The data is in longitudinal format. The study
 included 7 major time points. Each row in the data represents a single
 participant at a single time point. All participants included in this data
 set consented to sharing their data for additional research purposes
 outside of our lab. Seven participants included in our analysis DID NOT
 consent to this and therefore are not included in this data. Therefore any
 replication of our analysis plan will not match our original analysis as
 the sample is different. R scripts used in our analysis are included for
 reference. Data here was stored in REDCap. Any data containing personal
 identifiable information (name, email, phone, etc.) was marked as such in
 REDCap and not exported to this dataset. Unverified text and notebox
 fields were removed from this export. Date and timestamp fields were
 randomly adjusted by +/- 365 days to further enhance anonymity. ### Files
 and variables #### File:
 Maximizing_Outcomes_for_Toddlers_with_DLD_Data_Dictionary.csv
 **Description:**  ##### Variables * Variable / Field Name: Name of the
 variable * Form Name: Assessment or Survey from which the field was
 obtained * Field Type: Text entry, calculation, radio button, yes/no *
 Field Label: A description of the field * Choices or Calculations: Radio
 button options or calculated field equations * Field Note: Any additional
 notes about the field #### File:
 Maximizing_Outcomes_for_Toddlers_with_DLD_Data.csv **Description:**  All
 deidentified REDCap data used in the analysis phase of this study is
 included in this data set. Please use the data dictionary file for
 reference. ## Code/software Excel or R # Missing Data and Empty Cells
 Empty cells in the dataset represent intentionally missing values. No
 values have been removed or hidden. Blank cells occur for the following
 reasons: 1. **Not Yet Collected** – The measure was not administered at
 that time point (e.g., vocabulary assessments are not present at baseline;
 grammar assessments are not present at T36). 2. **Not Applicable** – The
 measure was not relevant for that participant (e.g., group-specific
 variables). 3. **Participant-Level Missingness** – The participant did not
 complete a specific assessment or was unavailable at that time point. 4.
 **Data Sharing Restrictions** – Seven participants who did not consent to
 additional data sharing have been removed entirely from this dataset;
 therefore, no partial records are present for those individuals. In this
 dataset, blank cells are intended to be interpreted as missing values
 (`NA`). When imported into R using standard functions (e.g., `read.csv()`
 or `readr::read_csv()`), blank cells will automatically be read as `NA`.
 No blank cells represent zero values. The accompanying analysis scripts
 assume that blank cells are read as `NA`. Users working in other
 statistical software should ensure that blank cells are treated as missing
 values. ## Analysis Scripts Included in Submission This submission
 includes two R scripts that reproduce the primary short-term outcome
 analyses reported in the associated manuscript. ### 1.
 `U01_Analysis_2-1_Dryad.Rmd` This script evaluates short-term vocabulary
 outcomes at 6 months post-baseline (T36; child age ~36 months). * Outcome:
 Latent variable representing **Short-Term Vocabulary** * Indicators: *
 Expressive Vocabulary Test–Third Edition (EVT-3) * Peabody Picture
 Vocabulary Test–Fifth Edition (PPVT-5) * Independent variable: * Treatment
 group (EMT-SF vs. control) * Covariate: * Baseline number of different
 words (NDW) from language sample The latent variable model is estimated
 using structural equation modeling (SEM). --- ### 2.
 `U01_Analysis_2-2_Dryad.Rmd` This script evaluates short-term grammar
 outcomes at 12 months post-baseline (T42; child age ~42 months). *
 Outcome: Latent variable representing **Short-Term Grammar** * Indicators:
 * Structured Photographic Expressive Language Test–Preschool, Second
 Edition (SPELT-P2) * Test of Early Grammatical Impairment (TEGI) *
 Independent variable: * Treatment group (EMT-SF vs. control) * Covariate:
 * Baseline language sample score The latent variable model is estimated
 using structural equation modeling (SEM). --- ## Missing Data Handling in
 Analysis Scripts Both scripts assume that blank cells in the dataset are
 read as missing values (`NA`) in R. Missing data are handled within the
 SEM framework using full information maximum likelihood (FIML), as
 specified in the analysis code. Blank cells in the dataset represent: *
 Structurally missing values (measure not administered at that time point)
 * Participant-level missingness (assessment not completed) * Not
 applicable values (measure not relevant for that participant) Blank cells
 do not represent zero values. Users working in other statistical software
 should ensure that blank cells are interpreted as missing values. --- ##
 Sample Size Note Seven participants who did not consent to additional data
 sharing are excluded from the shared dataset. As a result, reproduced
 estimates may differ slightly from those reported in the published
 manuscript. --- ## Software Requirements The scripts were written in R
 (version 4.4.1) and require the following packages: * lavaan * tidyverse
 (or specify exact packages used) Users should ensure required packages are
 installed prior to running the scripts. ## Human subjects data All
 participants included in this data set consented to sharing their data for
 additional research purposes outside of our lab. Seven participants
 included in our analysis DID NOT consent to this and therefore are not
 included in this data. Therefore any replication of our analysis plan will
 not match our original analysis as the sample is different. Data here was
 stored in REDCap. Any data containing personal identifiable information
 (name, email, phone, etc.) was marked as such in REDCap and not exported
 to this dataset. Unverified text and notebox fields were removed from this
 export. Date and timestamp fields were randomly adjusted by +/- 365 days
 to further enhance anonymity.