title: An Item Response Theory-Based, Computerized Adaptive Testing Version of the MacArthur-Bates Communicative Development Inventory: Words & Sentences (CDI:WS).
abstract: This study investigated the feasibility and potential validity of an item response theory (IRT)-based computerized adaptive testing (CAT) version of the MacArthur-Bates Communicative Development Inventory: Words & Sentences (CDI:WS; Fenson et al., 2007) vocabulary checklist, with the objective of reducing length while maintaining measurement precision.
  
  
  
  Parent-reported vocabulary for the American CDI:WS norming sample consisting of 1,461 children between the ages of 16 and 30 months was used to investigate the fit of the items to the 2-parameter logistic IRT model and to simulate CDI-CAT versions with 400, 200, 100, 50, 25, 10, and 5 items.
  
  
  
  All but 14 items fit the 2-parameter logistic IRT model, and real data simulations of CDI-CATs with at least 50 items recovered full CDI scores with correlations over .95. Furthermore, the CDI-CATs with at least 50 items had similar correlations with age and socioeconomic status as the full CDI:WS.
  
  
  
  These results provide strong evidence that a CAT version of the CDI:WS has the potential to reduce length while maintaining the accuracy and precision of the full instrument.
authors.forename: Guido
authors.initials: G
authors.lastname: Makransky
authors.forename: Philip S
authors.initials: PS
authors.lastname: Dale
authors.forename: Philip
authors.initials: P
authors.lastname: Havmose
authors.forename: Dorthe
authors.initials: D
authors.lastname: Bleses
mesh_terms: D002663:Child Language; D002675:Child, Preschool; D003142:Communication; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted; D005260:Female; D006801:Humans; D007223:Infant; D007807:Language Tests; D016015:Logistic Models; D008297:Male; D012660:Semantics; D013997:Time Factors; D014825:Vocabulary