The Parent’s Observations of Social Interactions (POSI), is a 7-item screening instrument for Autism Spectrum Disorders (ASD). The POSI was created as one part of a comprehensive screening instrument designed for pediatric primary care. Items for the POSI were chosen by a team of experts who reviewed existing assessment instruments and relevant research literature. Initial validation was conducted in two sub-studies, 1) in a sub-specialty setting and 2) in separate mixed sub-specialty/primary care settings. In the first sample, parents of 213 children aged 18-48 months who presented to a developmental clinic for diagnostic evaluation completed a clinical intake questionnaire that included the POSI and the Modified Checklist for Autism in Toddlers (M-CHAT) checklist. POSI and M-CHAT scores were compared to results of the full clinical evaluation to derive scoring thresholds and assess reliability and validity. In the second sample, 235 parents of children aged 16-36 months were enrolled from a combination of primary care and subspecialty settings. They completed the POSI, M-CHAT, and a report of their child’s diagnoses. POSI and M-CHAT scores were compared to reported diagnoses to assess validity. In the first study, the POSI demonstrated adequate internal reliability (Cronbach alpha 0.83). Sensitivity (89%) was higher than that of the MCHAT (71%) (p<0.05) and specificity (54%) was not significantly different from that of the MCHAT (62%). In the second study, the POSI demonstrated adequate internal reliability (alpha=0.86). Sensitivity (83%) compared favorably to the MCHAT (50%), although specificity was lower (75% v 84%).
The POSI was the outgrowth of a group of clinicians and research colleagues supported by a small grant from the Boston Autism Consortium. The group was generated and led by Dr. Alice Carter and consisted in addition of Marilyn Augustyn, Elizabeth Caronna, Alison Schonwald, Chris Sheldrick, and Ellen Perrin. The group met for several months to generate, format, and pilot test the questions that eventually became the seven-item POSI
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