The Index of Productive Syntax: Psychometric Properties and Suggested Modifications

Abstract

Purpose The Index of Productive Syntax (IPSyn) is a well-known language sample analysis tool. However, its psychometric properties have not been assessed across a wide sample of typically developing preschool-age children and children with language disorders. We sought to determine the profile of IPSyn scores by age over early childhood. We additionally explored whether the IPSyn could be shortened to fewer items without loss of information and whether the required language sample could be shortened from a current required number of 100 utterances to 50. Method We used transcripts from the Child Language Data Exchange System, including 1,051 samples of adult–child conversational play with toys within the theoretical framework of item response theory. Samples included those from typically developing children as well as children with hearing loss, Down syndrome, and late language emergence. Results The Verb Phrase and Sentence Structure subscales showed more stable developmental trajectories over the preschool years and greater differentiation between typical and atypical cohorts than did the Noun Phrase and Question/Negation subscales. A number of current IPSyn scoring items can be dropped without loss of information, and 50-utterance samples demonstrate most of the same psychometric properties of longer samples. Discussion Our findings suggest ways in which the IPSyn can be automated and streamlined (proposed IPSyn-C) so as to provide useful clinical guidance with fewer items and a shorter required language sample. Reference values for the IPSyn-C are provided. Trajectories for one subscale (Question/Negation) appear inherently unstable and may require structured elicitation. Potential limitations, ramifications, and future directions are discussed. Supplemental Material https://doi.org/10.23641/asha.16915690

Measurement of Lexical Diversity in Children’s Spoken Language: Computational and Conceptual Considerations

“…Low sensitivity to disorder might be counterbalanced by the ability of a measure to guide intervention. We and others have discussed this concept previously ( Overton et al, 2021 ; Yang et al, 2022 ) in relationship to some grammatical analyses of spoken language samples by indices such as Developmental Sentence Scoring ( Lee, 1974 ) or the Index of Productive Syntax ( Altenberg et al, 2018 ). In each of these cases, low diagnostic sensitivity can easily be balanced by the relatively rich information it can provide to the intervention process (e.g., Finestack et al, 2020 ; Pezold et al, 2020 ).…”

“…Participants were taken from CHILDES corpora in English/North America (NA) and the Clinical MOR English NA subdirectory. These are the same samples used by Yang et al (2022) , with one exception: no children with Hearing Loss were included in the current analysis due to extreme heterogeneity in lexical profiles on all measures we were studying. The number of samples per study and the descriptive statistics for gender and age for these three groups of children are presented in Table 1 .…”

“…In sum, given the set of findings presented here, until we identify more LSA measures that appear to perform well diagnostically, we suspect that both fair and informative language sample analysis for preschool aged children may need to rethink common recommendations to adjust the elicitation process for each child, merely to increase the child's likelihood of conversing with the parent or adult interlocutor. This call (see also Yang et al, 2022) to re-envision and standardize LSA prompts for both lexical and syntactic analysis would run directly counter to some currently advised by LSA specialists, who advise that "the play context can be adjusted to meet individual preferences, individual interests, gender, culture and experience" in the service of the largest possible sample (Miller et al, 2015, p. 13-14). While laudable in principle and client-centered focus, we do not currently appear to have lexical diversity measures for preschool children's LSA that satisfy basic requirements of such measures for either diagnostic or therapy planning purposes.…”

“…For children older than our target population (preschool), written NDW has a moderate correlation with standardized reading vocabulary measures ( Wood et al, 2019 ). However, attempting to create a single NDW elicitation standard for the preschool age range presents challenges: younger children (e.g., ages 2–3 years) are not able to produce reasonable narratives from prompts, and children with language delays are likely to be less talkative, making it difficult to standardize sampling sizes at numbers above 50 utterances ( Yang et al, 2022 ) within a single diagnostic session.…”

“…Some research has suggested that lexical diversity measured by VocD does differ by task even within a general genre, such as story telling compared to story retell ( Kapantzoglou et al, 2017 ). This, in turn, would suggest a need for standardizing language sampling contexts even within conversational interaction, a concept we have recently discussed in relation to another measure of child language growth, the Index of Productive Syntax (IPSyn; Yang et al, 2022 ).…”