To examine the effectiveness of our approach to designing items and individualized instructions, we undertook an evaluation process where we administered all items from ATLAS-PA to a group of children with typical development. We removed all misfitting items and subsequently administered ATLAS-PA to a group of children with speech and/or language impairment.
Participants
Two groups of children (N = 1,165 overall) ages 3;0 (years;months) to 7;11 took ATLAS-PA. The study design and materials were reviewed by the institutional review board at Michigan State University. The study (IRB X15-599e) was determined to be exempt under Category 1, as it only involved normal educational practices. Parents of participants provided written consent before participating, and children provided verbal and/or nonverbal assent before working with research assistants. Participants received a $10 gift card and a children's book for participating in the study.
The first group of children exhibited typical development as reported by parents and had no current Individualized Education Program (IEP) for speech and/or language impairments (n = 938 [445 girls], M age = 62.55 months, SD = 14.62 months). Recruitment occurred within 57 schools located in the Midwest. Children with typical development in this study were predominantly White/Caucasian (490 children [52.24%]), followed by Black/African American (223 [23.77%]), multiracial (119 [12.69%]), Asian/Pacific Islander (46 [4.90%]), Hispanic or Latino (40 [4.26%]), Native American (1 [0.11%]), or other (14 [1.49%]). Most parents reported that English was the primary language spoken within their homes (783 [83.48%]); inclusion criteria required parents to affirm that the participating child spoke English fluently. Of the parents who reported that they spoke another language at home, 46 languages were represented. Maternal education varied: some high school (68 mothers [7.25%]), high school diploma or equivalent (146 [15.57%]), some college (234 [24.95%]), undergraduate degree (220 [23.45%]), and graduate/professional school (230 [24.52%]). Annual household income also varied: less than $25,000 (330 households [35.18%]); $25,000–$49,999 (174 [18.55%]); $50,000–$74,000 (108 [11.51%]); $75,000–$99,999 (90 [9.59%]); and more than $100,000 (177 [18.87%]).
The second group of children had a reported speech and/or language impairment (n = 227 [77 girls], M age = 66.46 months, SD = 16.31 months). To be eligible for inclusion in the group of children with speech and/or language impairment, children needed to meet the following eligibility criteria: be between 3 and 7 years of age, have goals related to speech and/or language in an IEP, and have parents report that they could understand English in a way that is similar to a native speaker. Recruitment was done through flyers distributed and collected at 90 schools by special education coordinators, teachers, and speech-language pathologists who were familiar with our eligibility criteria. Parents were asked to confirm that children had IEP goals related to speech and/or language and were receiving services related to these areas. Similar to participants with typical development, children with speech and/or language impairment were predominantly White/Caucasian (130 [57.27%]), followed by Black/African American (48 [21.15%]), multiracial (27 [11.89%]), Hispanic or Latino (11 [4.85%]), or other (4 [1.76%]); however, there were fewer Asian/Pacific Islander children (1 [0.44%]; χ2 1 = 8.29, p < .01) than in the first group, with no Native American children represented. Additionally, most parents reported that English was the primary language spoken within their homes (205 [90.31%]); four other languages were reported to be spoken within participants' homes (i.e., Spanish, Burmese, Albanian, and American Sign Language). Maternal education and annual household income brackets were generally similar among both groups, though, for the second group, there were more mothers who reported having attended some college (χ 2 1 = 7.79, p < .01) or came from households with incomes of under $25,000 (χ2 1 = 4.68, p = .03), and fewer mothers in the second group held graduate degrees (χ2 1 = 5.81, p = .02) or had household incomes of $100,000 or greater (χ2 1 = 17.63, p < .01). Relatively, more boys were in the group with IEPs compared to the group of children with typical development (χ2 1 = 9.17, p < .01). For age distribution, we attempted to recruit similar numbers of children within each age bracket of 3- to 7-year-olds. The group with typical development had proportionally more 4-year-olds than the group with IEPs (χ2 1 = 19.16, p < .01), and there were proportionally more 6-year-olds in the second group than in the first (χ2 1 = 6.43, df = 1, p < .05), but the proportions of 3-, 5-, and 7-year-olds were not significantly different between the two groups.
The children with speech and/or language impairments represented a broad range of children, who had varying levels of speech production capabilities. In addition to having an IEP for speech/language, children were reported to have the following disabilities and/or impairments: autism spectrum disorder (20 [8.81%]), attention deficit (11 [4.85%]), intellectual disability (11 [4.85%]; includes cognitive impairment, global developmental delay, Down syndrome, and fetal alcohol syndrome), vision impairment (eight children [3.52%]), high social/emotional needs (seven [3.08%]), learning disability (six [2.64%]), hearing impairment (five [2.20%]), movement/coordination problem (three [1.32%]), physical disability (two [0.88%]), and/or cerebral palsy (two [0.88%]). Fifty-seven of the 227 children (25.11%) were reported to have at least one other developmental disability in addition to a speech and/or language impairment. See
Table 1 for demographic characteristics broken down by ability group.
Other Measures of PA
In addition to taking ATLAS-PA, children exhibiting typical development were administered two other measures of PA chosen based on the child's age relative to the valid age range of the measure. The other PA measures are not appropriate for all of the children with speech and/or language impairment and thus were not administered to this group.
TOPEL. For the children with typical development, all 3-year-olds and half of the 4- to 6-year-olds (
n = 442) were administered the PA subtest of the TOPEL (
Lonigan et al., 2007). This subtest requires children to put sounds together to form a new word (blending) and to remove sounds from a word to form a new word (elision). Children were given prompts such as, “Point to the word you get when you say ‘tooth’–‘brush’ together.” As reported in the test manual, the internal consistency of TOPEL PA is .87 and test–retest stability over a 2-week period was .83 (
Lonigan et al., 2007).
Comprehensive Test of Phonological Processing–Second Edition. For the children with typical development, half of the 4- to 6-year-olds were administered the ages 4–6 years version of the Blending and Elision subtests of the Comprehensive Test of Phonological Processing–Second Edition (
Wagner et al., 2013). All 7-year-olds with typical development were administered the ages 7–24 years version of the Blending and Elision subtests. The Elision subtest requires children to identify or name the word that remains when a part of the word has been removed. Items ranged between elision of compound words (e.g., toothpaste without tooth), of syllables (e.g., catcher without -er), and of phonemes (e.g., grain without -n). Blending involves combining words into compound words, syllables into words, and phonemes into words. The Blending and Elision subtest raw scores are converted to percentile ranks and scaled scores via score lookup tables to yield a composite PA score. Internal consistency for the Comprehensive Test of Phonological Processing–Second Edition PA composite score is .92 for the ages 4–6 years version and .93 for the ages 7–24 years version (
Wagner et al., 2013).
Preschool Early Literacy Indicators. For the children with typical development, all 3- and 4-year-olds (
n = 584) were administered the PA subtest of the Preschool Early Literacy Indicators (
Kaminski et al., 2018). This subtest assesses preschool-age children's ability to identify or say the first part or the first sound of a word (e.g., the first part of rainbow is rain). Interrater reliability ranges from .90 to .98.
DIBELS Next. Kindergarteners with typical development (
n = 136; the DIBELS Next is grade based rather than age based) received the First Sound Fluency (FSF) subtest of the DIBELS Next. FSF provides 1 min for children to say the first sounds of orally introduced words. In addition, for the children with typical development, all kindergarten, Grade 1, and Grade 2 children (
n = 340) received the Phoneme Segmentation Fluency subtest, which asks children to listen to orally introduced words and say all of the sounds in the word. The alternate-form reliability for the FSF and Phoneme Segmentation Fluency subtests is .72 and .88, respectively (
Dewey et al., 2012).
Analyses
We used a Rasch measurement approach to examine the construct validity of the item pool of the ATLAS-PA. Rasch measurement is a form of item response analysis that offers a strong approach to validation at the item level (
Bond & Fox, 2015;
Rost, 2001), yielding scores that have good evidence of interval scaling (
Perline et al., 1979). The specific model we used was the
Rasch (1960) model for dichotomous outcomes:
where
Pni is the probability of examinee
n with trait level θ
n (i.e., PA level) succeeding on item
i, which has difficulty level β
i . Data were analyzed using the Rasch measurement software Winsteps (
Linacre, 2018c). Because of the potential for guessing with multiple-choice items, we used the CUTLO = −1 option, which treats individual item responses with expected probability of correct response below .27 as missing. Alternative values for CUTLO yielded identical results.
To address the first research question regarding dimensionality, we used a Rasch principal components analysis of residuals (
Linacre, 1998). To address the second research question regarding item functioning, we examined the fit of the items to the Rasch model using standard Rasch fit statistics, Infit and Outfit. To address the third research question about differences in item functioning across gender and ability group (typically developing and speech and/or language impairment), we performed a differential item functioning (DIF) analysis. Finally, to address the fourth research question about nomothetic span, we examined correlations between scores from the ATLAS-PA and other measures of PA.