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J Autism Dev Disord (2011) 41:311319 DOI 10.1007/s10803-010-1057-0
ORIGINAL PAPER
Standardized ADOS Scores: Measuring Severity of Autism Spectrum Disorders in a Dutch Sample
Annelies de Bildt Iris J. Oosterling Natasja D. J. van Lang
Sjoerd Sytema Ruud B. Minderaa Herman van Engeland
Sascha Roos Jan K. Buitelaar Rutger-Jan van der Gaag Maretha V. de Jonge
Published online: 9 July 2010 The Author(s) 2010. This article is published with open access at Springerlink.com
Abstract The validity of the calibrated severity scores on the ADOS as reported by Gotham et al. (J Autism Dev Disord 39: 693705, 2009), was investigated in an independent sample of 1248 Dutch children with 1455 ADOS administrations (modules 1, 2 and 3). The greater comparability between ADOS administrations at different times, ages and in different modules, as reached by Gotham et al. with the calibrated severity measures, seems to be corroborated by the current study for module 1 and to a lesser
extent for module 3. For module 2, the calibrated severity scores need to be further investigated within a sample that resembles Gothams sample in age and level of verbal functioning.
Keywords ADOS Autism ASD Diagnosis
Symptoms Severity
Recently, Gotham et al. (2009) published calibrated severity scores for the Autism Diagnostic Observation Schedule (ADOS; Lord et al. 1999). Developing these calibrated severity scores was inspired by the need in clinical practice and research for describing the severity of the behavior of children with autism spectrum disorders (ASDs) referring to the core symptoms in the autism spectrum. The ADOS, as a well developed, valid instrument is widely used as an important part of the diagnostic procedure when investigating ASDs in clinical practice and research. The raw scores obtained by an ADOS administration are often used as a means to indicate severity of ASD, even though the ADOS was not specically developed to facilitate comparison of data from different modules, different moments of measurement or different children. Due to developmental differences between children administered the various modules, to the developmental grading of the items across modules, and to differences between the numbers of items across modules raw scores on the ADOS are not directly comparable.
Compared to the original algorithms (Lord et al. 1999), the revised algorithms (Gotham et al. 2007) increased comparability...